bluuebunny/crossref_metadata_2025 huggingface dataset:
Videodensitometric analysis of human coronary stenoses: validation in vivo by intraoperative high-frequency epicardial echocardiography.
Authors: Johnson M R , McPherson D D , Fleagle S R , Hunt M M , Hiratzka L F , Kerber R E , Marcus M L , Collins S M , Skorton D J
Published: June 2011

Videodensitometry is a nongeometric method of coronary angiographic analysis that can be used to provide an index of coronary luminal area. However, there are few direct studies in vivo of the relationship of videodensitometric data to independent measures of luminal area in humans. Although videodensitometry is theoretically independent of angiographic projection and luminal shape, validation of these assumptions in vivo is also limited. We therefore used intraoperative high-frequency epicardial echocardiography, a technique that can directly determine human coronary luminal area and shape in vivo, to further validate videodensitometry. A total of 36 arterial segments in the left anterior descending and right coronary arteries were studied by videodensitometry and high-frequency echocardiography. Videodensitometry was performed on angiograms in which the arterial segment of interest was not markedly foreshortened and was uniformly filled with contrast. In 22 discrete lesions (13 with circular lumens and nine with oval or complex lumens), videodensitometric and echocardiographic measures of luminal area correlated well (r = .86). In 33 coronary arterial segments, the effect of angiographic projection on videodensitometry was determined by comparison of the results of videodensitometry performed on left anterior oblique vs right anterior oblique angiograms of the segments. Here too, the correlation was good (r = .94, y = 1.04x + 0.002). The good correlation of left anterior oblique with right anterior oblique videodensitometric results held true for lesions with circular and oval or complex lumens. This study further validates the ability of videodensitometry to provide an index of coronary luminal area and confirms in vivo previous assumptions that the results of videodensitometric analysis are independent of angiographic projection and luminal shape.
The Western Washington Intravenous Streptokinase in Acute Myocardial Infarction Randomized Trial.
Authors: Kennedy J W , Martin G V , Davis K B , Maynard C , Stadius M , Sheehan F H , Ritchie J L
Published: June 2011

Three hundred sixty-eight patients were randomly assigned to receive intravenous streptokinase (IVSK) (n = 191) or standard therapy (n = 177) to determine the efficacy of IVSK in the treatment of acute myocardial infarction. The mean time to treatment was 3.5 hr. At 14 days there were 12 deaths in the treatment group (6.3%) and 17 deaths in the control group (9.6%) (p = .23). Early mortality was related to infarct location. Fourteen day mortality for anterior infarctions was 10.4% for treatment with IVSK and 22.4% for control patients (p = .06) and was similar for IVSK-treated patients with inferior infarctions, 4.0% vs 1.8% (p = .32). For those randomized under 3 hr, 14 day mortality tends to be lower in treated patients, 5.2% vs 11.5% (p = .11). There was significant improvement in long-term survival for patients with anterior infarction; 2 year survival was 81% for IVSK-treated patients and 65% for control patients (p = .05). There was no improvement in survival for patients with inferior myocardial infarction (p = .27). We conclude that patients with anterior myocardial infarction have improved survival when treated within the first 6 hr of symptoms. Patients with inferior infarction do not appear to have improved survival with thrombolytic therapy. Some of this improvement in survival in patients with anterior infarction may be due to a higher frequency of revascularization procedures in the treatment group.
Angiographic and clinical predictors of acute closure after native vessel coronary angioplasty.
Authors: Ellis S G , Roubin G S , King S B , Douglas J S , Weintraub W S , Thomas R G , Cox W R
Published: June 2011

To determine predictors of acute coronary closure after PTCA performed with steerable catheter systems, we compared 140 procedures complicated by acute closure and 311 representative successful attempts from 4,772 procedures performed between April 1982 and March 1986. Sixteen clinical, 35 angiographic, and seven procedural variables were analyzed. Multivariate analysis found seven independent preprocedural factors related to closure: stenosis length of 2 or more luminal diameters, female gender, stenosis at a bend point of 45 degrees or more, stenosis at a branch point, stenosis-associated thrombus (filling defect or staining), other stenoses in the same vessel, and multivessel disease. In addition, four procedural factors were found to be associated with closure by univariate analysis: post-PTCA percent stenosis (p less than .001), intimal tear or dissection (p less than .001), use of prolonged heparin infusion (p less than .001), and post-PTCA gradient of 20 mm Hg or more (p = .004). Multivariate analysis of both preprocedural and procedural variables found six factors independently related to closure: post-PTCA percent stenosis, dissection, prolonged post-PTCA use of heparin, branch point location, fixed bend point location, and other stenoses in the vessel dilated. The risk of coronary closure after PTCA has many determinants. While an estimation of risk can be made before performing PTCA, the most powerful predictors of closure can only be assessed during the procedure itself.
Quantification of absolute luminal diameter by computer-analyzed digital subtraction angiography: an assessment in human coronary arteries.
Authors: Rosenberg M C , Klein L W , Agarwal J B , Stets G , Hermann G A , Helfant R H
Published: June 2011

Determination of absolute lumen diameters has been shown to be useful in predicting the functional importance of a coronary stenosis. In this study, both single-plane and orthogonal biplane digital subtraction angiograms were obtained in human cadaver coronary arteries. A single absolute diameter was calculated at the site of greatest narrowing in 20 segments by two automated computerized algorithms. Minimum and maximum diameters at the site of the stenosis were measured from pathologic sections prepared after pressure fixation. Method 1, which determines the edges by means of the first derivative of the videodensity curve, derived absolute diameters that fell between the pathologic minimum and maximum in 10 of 20 segments. Method 2, which determines the edges by an average of the first and second derivatives of the videodensity change, derived absolute diameters that fell between the pathologic minimum and maximum diameters in 15 of 20 segments. Method 1 correlated well with the maximum pathologic diameter (r = .76) and less well with the minrmum pathologic diameter (r = .67). Method 2 correlated very well with the maximum pathologic diameter (r = .79) and also correlated well with the minimum pathologic diameter (r = .74). As would be expected, the computerized algorithms tended to overestimate the minimum pathologic diameter and to underestimate the maximum pathologic diameter. In six segments, two orthogonal views were analyzed; no further accuracy was discernible over single-plane determinations. Thus quantitative coronary angiography by digital subtraction angiography is sufficiently accurate to be of use in the measurement of the severity of a coronary stenosis.
Mortality associated with diastolic hypertension and isolated systolic hypertension among men screened for the Multiple Risk Factor Intervention Trial.
Authors: Rutan G H , Kuller L H , Neaton J D , Wentworth D N , McDonald R H , Smith W M
Published: June 2011

The large cohort of white men (317,871) 35 to 57 years old at initial screening for possible enrollment into the Multiple Risk Factor Intervention Trial (MRFIT) was examined with regard to initial blood pressure levels and subsequent coronary heart disease (CHD), stroke, and all-cause mortality. The overall prevalence of isolated systolic hypertension (ISH), defined as systolic blood pressure (SBP) greater than or equal to 160 mm Hg and diastolic blood pressure (DBP) less than 90 mm Hg, was 0.67% among white men screened for MRFIT and increased with age (0.31% among 35- to 39-year-olds to 1.7% among 55- to 57-year-olds). The 6 year CHD and all-cause mortality rates in men over 50 were highest in those with ISH compared with both subjects with diastolic hypertension and those with normal pressure. The relative risk of death from stroke in those with ISH, compared with that in those with SBP less than 160 mm Hg and those with DBP less than 90 mm Hg, was 3.0 (95% confidence interval 1.3 to 6.8). In addition, at any level of DBP, the level of SBP appeared to be the major determinant of all-cause and CHD mortality. The determinants of ISH in individuals under 60 years of age as well as the possible efficacy of its treatment should be evaluated further.
Multivessel coronary spasm in patients with variant angina: a study with intracoronary injection of acetylcholine.
Authors: Okumura K , Yasue H , Horio Y , Takaoka K , Matsuyama K , Kugiyama K , Fujii H , Morikami Y
Published: June 2011

Multivessel coronary spasm has been described but its incidence in patients with variant angina still remains unclear. Thirty-three patients with variant angina were studied during coronary angiographic examination with selective intracoronary injection of acetylcholine (ACh). In all but three patients, the location of ischemia during attack was determined by the electrocardiographic findings, by exercise 201Tl myocardial scintigraphy, and by two-dimensional echocardiography during a hyperventilation test, and the coronary artery (or arteries) responsible for the attack was predicted before the study. ACh induced spasm of at least one coronary artery in all but one patient. ACh induced spasm of both the left and right coronary arteries (i.e., multivessel coronary spasm) in 24 patients: in two of the four patients who were predicted to have spasm of the left coronary artery, in six of the 11 predicted to have spasm of the right coronary artery, in 13 of the 15 predicted to have spasm of both the left and right coronary arteries, and in three of the three in whom coronary artery responsible for attack had not been predicted. This ACh-induced spasm of the left and right coronary arteries occurred separately and no patients showed hemodynamic instability during attack. In one patient in whom multivessel coronary spasm had been predicted and ACh failed to induice coronary spasm, ergonovine maleate (0.2 mg) induced spasm of both the left and right coronary arteries simultaneously, resulting in severe prolonged hypotension. Nineteen of the 25 patients in whom multivessel coronary spasm was documented showed angiographically normal or nearly normal coronary arteries after administration of nitroglycerin.(ABSTRACT TRUNCATED AT 250 WORDS)
Rapid and sustained coronary artery recanalization with combined bolus injection of recombinant tissue-type plasminogen activator and monoclonal antiplatelet GPIIb/IIIa antibody in a canine preparation.
Authors: Gold H K , Coller B S , Yasuda T , Saito T , Fallon J T , Guerrero J L , Leinbach R C , Ziskind A A , Collen D
Published: June 2011

The effects of bolus injections of recombinant single-chain tissue-type plasminogen activator (rt-PA) and of F(ab')2 fragments of a murine monoclonal antibody (7E3) against the human platelet GPIIb/IIIa receptor [7E3-F(ab')2] on coronary arterial thrombolysis and reocclusion was studied in a canine preparation of coronary artery thrombosis superimposed on high-grade stenosis. Bolus intravenous injections of rt-PA at a dose of 0.45 mg/kg, repeated at 15 min intervals until reperfusion occurred (maximum of four injections) caused reperfusion in five of seven dogs within 100 min (33 +/- 15 min, mean +/- SD). Reperfusion was rapidly followed (generally within 10 min) by reocclusion and then by periods of cyclical reflow and reocclusion. A single intravenous injection of 7E3-F(ab')2 alone at 0.8 mg/kg caused reperfusion within 100 min in two of six dogs (19 and 37 min) without subsequent reocclusion. Single bolus injections of different amounts (0.1 to 0.8 mg/kg) of 7E3-F(ab')2 were then combined with bolus injections of 0.45 mg/kg of rt-PA. Stable reperfusion without reocclusion was accomplished with 0.8 or 0.6 mg/kg 7E3-F(ab')2 and a single injection of 0.45 mg/kg rt-PA within 6 +/- 3 min (n = 6, p less than .01) and 8 +/- 5 min (n = 5, p less than .02), respectively. None of these animals suffered reocclusion of the coronary artery. Lower doses (0.1 to 0.2 mg/kg) of 7E3-F(ab')2 did not significantly shorten the time to reperfusion and did not prevent reocclusion.(ABSTRACT TRUNCATED AT 250 WORDS)
Prognostic utility of the exercise thallium-201 test in ambulatory patients with chest pain: comparison with cardiac catheterization.
Authors: Kaul S , Lilly D R , Gascho J A , Watson D D , Gibson R S , Oliner C A , Ryan J M , Beller G A
Published: June 2011

The goal of this study was to determine the prognostic utility of the exercise thallium-201 stress test in ambulatory patients with chest pain who were also referred for cardiac catheterization. Accordingly, 4 to 8 year (mean +/- 1SD, 4.6 +/- 2.6 years) follow-up data were obtained for all but one of 383 patients who underwent both exercise thallium-201 stress testing and cardiac catheterization from 1978 to 1981. Eighty-three patients had a revascularization procedure performed within 3 months of testing and were excluded from analysis. Of the remaining 299 patients, 210 had no events and 89 had events (41 deaths, nine nonfatal myocardial infarctions, and 39 revascularization procedures greater than or equal to 3 months after testing). When all clinical, exercise, thallium-201, and catheterization variables were analyzed by Cox regression analysis, the number of diseased vessels (when defined as greater than or equal to 50% luminal diameter narrowing) was the single most important predictor of future cardiac events (chi 2 = 38.1) followed by the number of segments demonstrating redistribution on delayed thallium-201 images (chi 2 = 16.3), except in the case of nonfatal myocardial infarction, for which redistribution was the most important predictor of future events. When coronary artery disease was defined as 70% or greater luminal diameter narrowing, the number of diseased vessels significantly (p less than .01) lost its power to predict events (chi 2 = 14.5). Other variables found to independently predict future events included change in heart rate from rest to exercise (chi 2 = 13.0), ST segment depression on exercise (chi 2 = 13.0), occurrence of ventricular arrhythmias on exercise (chi 2 = 5.9), and beta-blocker therapy (chi 2 = 4.3). The exclusion of myocardial revascularization procedures as an event did not change the results significantly. Although the number of diseased vessels was the single most important determinant of future events, the exercise thallium-201 stress test when considered as a whole (which included the number of segments demonstrating redistribution on delayed thallium-201 images, change in heart rate from rest to exercise, ST segment depression on the electrocardiogram, and ventricular premature beats on exercise) was equally powerful (chi 2 = 41.6). Combination of both catheterization and exercise thallium-201 data was superior to either alone (chi 2 = 57.5) for determining future events. Exercise stress test alone (without thallium-201 data) was inferior to the exercise thallium-201 stress test or cardiac catheterization for predicting future events (chi 2 = 30.6).(ABSTRACT TRUNCATED AT 400 WORDS)
Diltiazem, nifedipine, and their combination in patients with stable angina pectoris: effects on angina, exercise tolerance, and the ambulatory electrocardiographic ST segment.
Authors: Frishman W , Charlap S , Kimmel B , Teicher M , Cinnamon J , Allen L , Strom J
Published: June 2011

The efficacy and safety of oral nifedipine and diltiazem were compared in 20 patients with stable angina pectoris with use of a placebo run-in, randomized, double-blind titration to maximal effect crossover protocol. The effects of treatment withdrawal were also analyzed. All patients received placebo for 2 weeks and were then randomly assigned to receive either diltiazem or nifedipine. A 2 week drug titration phase in which patients received either diltiazem (180 to 360 mg/day) or nifedipine (30 to 120 mg/day) in three divided doses was followed by a 1 week maintenance phase. Patients then received placebo for 1 to 2 weeks, followed by crossover to the other treatment regimen and a second placebo washout period of 1 week. Patients (n = 13) who remained symptomatic on both diltiazem and nifedipine during the monotherapy periods entered a 3 week combination treatment phase, followed by a final 1 week placebo washout period. Frequency of angina, nitroglycerin consumption, exercise tolerance (Naughton protocol), and frequency of daily episodes of ST segment deviations on the electrocardiogram (1 mm of ST segment depression persisting for at least 1 min with and without chest pain) on an ambulatory electrocardiographic monitor were assessed during the baseline placebo, active monotherapy, placebo withdrawal, and combination treatment phases. Plasma drug levels were also measured. Compared with initial placebo values, the frequency of angina and the amount of nitroglycerin treatment were reduced by both diltiazem (p less than .001) and nifedipine (p less than .02). Diltiazem was more effective than nifedipine in reducing angina (p less than .02). Exercise duration increased with both drugs (p less than .0001). Diltiazem was significantly better than nifedipine in reducing the episodes of ST segment depression on the ambulatory monitor (p less than .01). Diltiazem reduced the resting heart rate (p less than .01); both drugs reduced the resting blood pressure and rate-pressure product. Overall, combination therapy was more effective in patients who did not maximally respond to diltiazem or nifedipine alone with respect to anginal and exercise variables and in reducing blood pressure at rest and during exercise. Plasma drug levels could not predict an individual patient's treatment response. Diltiazem may increase nifedipine drug levels when the drugs are combined. Fewer side effects were observed with diltiazem than nifedipine; the most side effects were seen with combination treatment. There were no apparent withdrawal effects observed with either treatment regimen.(ABSTRACT TRUNCATED AT 400 WORDS)
Combined use of nitroglycerin and N-acetylcysteine in the management of unstable angina pectoris.
Authors: Horowitz J D , Henry C A , Syrjanen M L , Louis W J , Fish R D , Smith T W , Antman E M
Published: June 2011

The vasodilator effects of nitroglycerin (NTG) are mediated via activation of guanylate cyclase; this process is believed to require the availability of free sulfhydryl groups. Previous studies in man have shown that the sulfhydryl donor N-acetylcysteine (NAC) potentiates the systemic and coronary vasodilator effects of NTG. Furthermore, interaction of NTG and NAC may lead to the formation of S-nitroso-NAC, which strongly inhibits platelet aggregation. The effects of intravenous NTG combined with intravenous NAC (5 g 6 hourly) were compared with those of intravenous NTG alone in a double-blind trial in 46 patients with severe unstable angina pectoris unresponsive to conventional treatment, which included calcium antagonists and cutaneous nitrates in all but one patient. Treatment with NTG/NAC (24 patients) and that with NTG alone (22 patients) was associated with a similar frequency of episodes of chest pain and of increments in NTG infusion rate for pain control (10 vs 17; p = NS). The NTG/NAC group had a significantly lower incidence of acute myocardial infarction than the NTG/placebo group (three vs 10 patients; p = .013). Symptomatic hypotension occurred frequently in the NTG/NAC group (seven vs 0 patients; p = .006). Lactate-pyruvate ratios and venous NTG concentrations were not significantly affected by NAC. Subsequently, another 20 consecutive patients were treated with intravenous NTG and continuously infused NAC (10 g/day). Seven remained pain free during the first 24 hr of NTG infusion; 11 required increments in NTG infusion rate for pain control. Acute myocardial infarction occurred in one patient, while none developed symptomatic hypotension.(ABSTRACT TRUNCATED AT 250 WORDS)
Mitral valve prolapse in patients with prior rheumatic fever.
Authors: Lembo N J , Dell'Italia L J , Crawford M H , Miller J F , Richards K L , O'Rourke R A
Published: June 2011

It is known that rheumatic heart disease frequently results in isolated mitral regurgitation without concomitant mitral stenosis, especially in countries with a high prevalence of rheumatic fever. However, more recent surgical pathologic data also have demonstrated a high incidence of mitral valve prolapse in cases of rheumatic heart disease, which suggests that rheumatic fever may be a cause of mitral valve prolapse. To determine whether this association of mitral valve prolapse and rheumatic heart disease is present in a stable clinic population, we studied 30 patients who had an apical systolic murmur and a well-documented history of rheumatic fever with dynamic auscultation, two-dimensional echocardiography, and pulsed Doppler examinations. Twenty of the 30 patients (67%) had findings on physical examination consistent with isolated mitral regurgitation and 25 patients (84%) had mitral regurgitation by Doppler examination. Echocardiography demonstrated mitral valve prolapse in 24 patients (80%), whereas only one of the total study group had echocardiographic findings consistent with mitral stenosis. We conclude that (1) the presence of an isolated systolic murmur in patients with a history of rheumatic fever frequently represents pure mitral regurgitation secondary to mitral valve prolapse and (2) postinflammatory changes in valvular tissue resulting from rheumatic fever may be the etiology of mitral valve prolapse in these patients.
Improvement in exercise capacity and exercise hemodynamics 3 months after double-balloon, catheter balloon valvuloplasty treatment of patients with symptomatic mitral stenosis.
Authors: McKay C R , Kawanishi D T , Kotlewski A , Parise K , Odom-Maryon T , Gonzalez A , Reid C L , Rahimtoola S H
Published: June 2011

Clinical status, exercise treadmill performance, and hemodynamics were determined in 24 patients with symptomatic mitral stenosis before catheter balloon valvuloplasty (CBV) and at 3 months follow-up. Hemodynamic determinations at rest showed that mitral CBV performed by the double-balloon technique resulted in significant immediate decreases in mean pulmonary arterial wedge pressure (28 +/- 7 to 16 +/- 5 mm Hg, p less than .01), mean pulmonary arterial pressure (41 +/- 11 to 33 +/- 10 mm Hg, p less than .05), and mitral valve gradient (16 +/- 7 to 6 +/- 3 mm Hg, p less than .01), and significant increases in cardiac output (4.3 +/- 1.1 to 5.0 +/- 1.4 liters/min, p less than .01). Mitral valve area increased from 1.0 +/- 0.3 to 2.2 +/- 0.7 cm2 (p less than .01). The mitral valve area was unchanged (2.0 +/- 0.7 cm2, p = NS) at 3 months. The lower pulmonary arterial wedge pressure, pulmonary arterial pressure, and mitral valve gradient persisted at 3 month follow-up catheterization. Clinical examinations showed that before CBV, 21 of 24 patients were in New York Heart Association functional class III or IV; 3 months after CBV, 22 patients were in class I or II. Before CBV, the mean exercise treadmill time was 5.9 +/- 3.2 min and it had increased to 9.8 +/- 2.9 min (p less than .01) by the 3 month follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
Improvement of treadmill capacity and collateral circulation as a result of exercise with heparin pretreatment in patients with effort angina.
Authors: Fujita M , Sasayama S , Asanoi H , Nakajima H , Sakai O , Ohno A
Published: June 2011

It has been demonstrated in animal experiments that heparin accelerates the coronary collateral development induced by repeated coronary occlusion. We used this effect of heparin for the treatment of patients with stable effort angina. In 10 patients, treadmill exercise was performed according to standard Bruce protocol twice a day for 10 days. A single intravenous dose of heparin (5000 IU) was given 10 to 20 min before each exercise period. Exercise with heparin pretreatment increased the total exercise duration from 6.3 +/- 1.9 (SD) to 9.1 +/- 2.2 min (p less than .001) and the maximal double product (DP) from 18,900 +/- 5100 to 25,500 +/- 6800 mm Hg.beats/min (p less than .001). The DP at the onset of angina was also increased by 35% (p less than .01) and the DP at which ST depression (0.1 mV) first appeared was 19% (p less than .05) greater after treatment. Repeat coronary cineangiography revealed an increase in the extent of opacification of collaterals to the jeopardized myocardium. In an additional six patients, treadmill exercise was performed with no medication twice a day for 10 days. All of the above-mentioned variables of treadmill capacity remained unchanged, despite 20 exercise periods without heparin pretreatment. Thus, heparin accelerates exercise-induced coronary collateral development by promoting angiogenesis. The development of such a therapeutic modality will open a new field for the treatment of patients with ischemia.
The effect of hypertension and left ventricular hypertrophy on the lower range of coronary autoregulation.
Authors: Harrison D G , Florentine M S , Brooks L A , Cooper S M , Marcus M L
Published: June 2011

These studies were performed to test the hypothesis that left ventricular hypertrophy arising as a complication of chronic hypertension is associated with impaired coronary autoregulation. Twelve dogs with hypertension and left ventricular hypertrophy (one-kidney, one-clip model) and 11 normal dogs were instrumented and subsequently studied while conscious. Circumflex pressure, measured with an intracoronary catheter, was adjusted to 100, 75, and 40 mm Hg with a hydraulic occluder that was placed proximally. At each circumflex pressure, myocardial perfusion was measured with radioactive microspheres. Reduction of circumflex pressure over this range did not significantly alter heart rate, left atrial pressure, or arterial pressure. In normal dogs, reduction of circumflex pressure did not alter total myocardial perfusion or the transmural distribution of perfusion. In contrast, in dogs with hypertension and left ventricular hypertrophy, circumflex subendocardial perfusion decreased 46% when pressure was decreased from 100 to 40 mm Hg (p less than .05 compared with normal). Autoregulation was quantified for each third of myocardium with the use of autoregulatory gain values (1 = perfect autoregulation; 0 = the absence of autoregulation). For pressure changes of 100 to 75 mmHg, values for autoregulatory gain were near unity for all layers of myocardium in both groups of animals. When pressure was decreased from 75 to 40 mm Hg, values for autoregulatory gain among the normal and hypertensive groups were, respectively: for subepicardium 1 +/- 0.2 (mean +/- SE) vs 0.9 +/- 0.2 (p = NS), for the midwall 0.8 +/- 0.2 vs 0.5 +/- 0.2 (p = NS), and for the subendocardium 0.8 +/- 0.1 vs 0.1 +/- 0.2 (p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
Serum Lp(a) level as a predictor of vein graft stenosis after coronary artery bypass surgery in patients.
Authors: Hoff H F , Beck G J , Skibinski C I , Jürgens G , O'Neil J , Kramer J , Lytle B
Published: June 2011

Although the serum lipoprotein fraction Lp(a) has been associated with coronary artery atherosclerosis, its relationship to narrowing of saphenous vein grafts has not previously been elucidated. We therefore measured serum Lp(a) levels in 167 symptomatic patients undergoing cardiac catheterization who had had coronary artery bypass surgery 0.7 to 14.3 years earlier. Lp(a), total cholesterol, and total triglyceride levels were compared with the degree of saphenous vein graft stenosis to test for any association. Serum Lp(a) levels were significantly associated with the degree of stenosis of saphenous vein grafts (r = .24, p = .002). Mean Lp(a) levels (mg/dl) in the 135 patients with stenosis were almost double (32.0 +/- 32.7, mean +/- SD) those in the 32 patients with no graft stenosis (16.7 +/- 22.6; p = .002). Graft stenosis was not associated with previous myocardial infarction, hypertension, obesity, diabetes, or smoking. Serum cholesterol levels (mg/dl) were slightly higher in the stenosis group (251.3 +/- 69) than in the no-stenosis group (231.8 +/- 48.8), but the difference was of borderline significance (p = .06). A stepwise increase in mean Lp(a) was found in groups of patients with increasing vein graft stenosis. At a serum Lp(a) level of 31.6 mg/dl or above, 92% of the patients demonstrated vein graft stenosis. Thus, patients with elevated Lp(a) levels have an increased risk of developing saphenous vein graft stenosis after coronary bypass surgery.
Limitation of myocardial infarction by early infusion of recombinant tissue-type plasminogen activator.
Authors: O'Rourke M , Baron D , Keogh A , Kelly R , Nelson G , Barnes C , Raftos J , Graham K , Hillman K , Newman H
Published: June 2011

In a double-blind randomized trial involving five Sydney hospitals and the city ambulance paramedical service, 145 patients with a first evolving myocardial infarction and with onset of pain less than 2.5 (mean 1.9 +/- 0.5 [SD]) hr previously were allocated to intravenous infusion of 100 mg recombinant tissue-type plasminogen activator (rt-PA) or placebo over 3 hr. The groups at entry were similar. At assessment 21 days later, left ventricular ejection fraction measured both by contrast and radionuclide ventriculography was higher in the rt-PA compared with the placebo group (61 +/- 13%, n = 64, vs 54 +/- 14%, n = 62, contrast, 2p = .006; 52 +/- 13%, n = 66, vs 48 +/- 13%, n = 62 isotope, 2p = .08). This indicates limitation of myocardial infarction by rt-PA.
Improvement in early saphenous vein graft patency after coronary artery bypass surgery with antiplatelet therapy: results of a Veterans Administration Cooperative Study.
Authors: Goldman S , Copeland J , Moritz T , Henderson W , Zadina K , Ovitt T , Doherty J , Read R , Chesler E , Sako Y
Published: June 2011

To determine whether specific antiplatelet therapies improved vein graft patency after coronary artery bypass grafting (CABG) we compared (1) aspirin, 325 mg daily, (2) aspirin, 325 mg three times daily, (3) aspirin plus dipyridamole (325 mg and 75 mg, respectively, three times daily), (4) sulfinpyrazone (267 mg three times daily), and (5) placebo (three times daily). Therapy, except aspirin, was started 48 hr before CABG. When aspirin was a treatment, one 325 mg dose was given 12 hr before surgery and therapy was maintained thereafter according to the assigned regimen. Angiographic graft patency data were obtained within 60 days of surgery. Analysis of early graft patency in 555 patients (1781 grafts), revealed the following graft patency rates: aspirin daily, 93.5%; aspirin three times daily, 92.3%; aspirin and dipyridamole, 91.9%; and sulfinpyrazone, 90.2%. All aspirin-containing therapeutic regimens improved (p less than .05) graft patency compared with placebo (85.2%). Chest tube drainage measured within the first 35 hr after CABG revealed that the median loss with aspirin daily (965 ml), aspirin three times daily (1175 ml), and aspirin plus dipyridamole (1000 ml) exceeded (p less than .02) that with placebo (805 ml), while median loss with sulfinpyrazone (775 ml) did not. The reoperation rate was greater (p less than .01) in all the treatment groups that received aspirin (6.5%) compared with the two nonaspirin groups (1.7%). Overall operative mortality was 2.3%, without significant differences among treatment groups. Transient renal insufficiency occurred in 5.3% of patients taking sulfinpyrazone. Thus, early vein graft patency was improved after CABG with all aspirin-containing drug regimens.(ABSTRACT TRUNCATED AT 250 WORDS)
Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data.
Authors: Wernovsky G , Hougen T J , Walsh E P , Sholler G F , Colan S D , Sanders S P , Parness I A , Keane J F , Mayer J E , Jonas R A
Published: June 2011

Although the short-term results of atrial level repair of transposition of the great arteries (TGA) are satisfactory, longer follow-up has disclosed a significant incidence of systemic right ventricular dysfunction and rhythm disturbances. The arterial switch operation (ASO) may represent a major improvement by restoring the left ventricle as the systemic ventricle and avoiding extensive atrial surgery. We have prospectively evaluated 49 consecutive survivors of ASO for TGA with intact ventricular septum (IVS) by clinical examination, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and invasive electrophysiologic studies. The mean length of follow-up has been 29 +/- 14 (SD) months after surgery. All children are currently asymptomatic and on no medications. Severe supravalvular pulmonary stenosis (greater than 60 mm Hg) was present in five children, all of whom have undergone reoperation. No patient has severe supravalvular aortic obstruction. Mild degrees of supravalvular pulmonary or aortic obstruction have not progressed. Seven children (14%) have trivial or mild aortic regurgitation. Two children have proximal occlusion of the left anterior descending coronary artery with adequate retrograde collateral perfusion. One child had an electrocardiographic pattern of inferior myocardial infarction without evidence of ventricular dysfunction. Systemic (left) ventricular function is normal as measured by end-diastolic pressure (mean 7 +/- 6 mm Hg), ejection fraction (mean 68 +/- 6%), end-diastolic volume (mean 101 +/- 22% of predicted normal), and cardiac index (mean 4.7 +/- 1.3 liters/min/m2). Only one patient has sinus node dysfunction. There have been no late deaths. These early results are encouraging. We conclude that the arterial switch operation is currently the procedure of choice for neonates with TGA and IVS.
Modulation of conduction slowing in ischemic rabbit myocardium by calcium-channel activation and blockade.
Authors: Kabell G
Published: June 2011

Ventricular action potentials and longitudinal conduction times over short distances of epicardium were recorded in isolated rabbit hearts. Global ischemia produced a progressive decrease of resting membrane potential, depression of action potentials, and conduction slowing to approximately 50% of control values over 8 to 10 min. Verapamil (2 X 10(-6) M) markedly attenuated ischemia-induced conduction slowing in association with less depression of maximum upstroke velocity (Vmax) and slightly less change in resting membrane potential. In contrast, Bay K 8644 (10(-7) M), a calcium-channel agonist, exacerbated ischemia-induced conduction slowing and depression of Vmax but did not significantly affect resting membrane potential. Regression analysis of Vmax vs resting membrane potential and the square of conduction velocity vs Vmax demonstrated that verapamil and Bay K 8644 shifted these relationships in opposite directions. The results indicate that the calcium-channel activation state can modulate slowing of conduction during early ischemia. This is most likely due to alterations in calcium influx before and/or during ischemia. There appear to be three possible components to this effect: (1) a small alteration in the magnitude of ischemia-induced depolarization, (2) alterations of membrane responsiveness at depolarized values of resting membrane potential, and (3) alterations in "nonactive" components of conduction during ischemia, such as changes in excitability or cell-to-cell coupling.
Value of digital image processing of two-dimensional echocardiograms in differentiating active from chronic vegetations of infective endocarditis.
Authors: Tak T , Rahimtoola S H , Kumar A , Gamage N , Chandraratna P A
Published: June 2011

The ability of a computer-based image digitizing system to differentiate "active" from "chronic" valvular vegetations was evaluated. Twenty-two patients with newly diagnosed infective endocarditis were studied prospectively by serial two-dimensional echocardiograms. Two comparable images (active and chronic) from the same patient taken several weeks apart (range, 4-17 weeks) after initiation of therapy were obtained at end diastole with identical gain settings. The images were digitized, magnified, and displayed on a high-resolution color monitor. The mean pixel intensity of the valvular vegetation in the active stage was 20.6 +/- 3.6 (mean +/- SD), which increased to 34.4 +/- 4.3 in the chronic stage (p less than 0.01). Because there was some overlap of values, an additional standardization procedure was used in the last eight patients. In these eight patients, the mean pixel intensity of the vegetations in the active stage was 17.5 +/- 1.1, and it increased at 4 weeks to 25.0 +/- 1.2 (p less than 0.05) and further increased in the chronic stage to 33.6 +/- 3.1 (p less than 0.05). There was no overlap of values between the active and chronic stages. Three clinical states are of particular interest: 1) The mean pixel intensity of the vegetations remained unchanged (23 vs. 24) in one patient who did not respond to antibiotic therapy. 2) The mean pixel intensity of the vegetations fell from 35 to 24 when one patient developed reinfection of the same valve, and with treatment, mean pixel intensity once again increased to 34. 3) The mean pixel intensity of the vegetations in five patients with culture negative infective endocarditis was low (21.6 +/- 1.9) and increased (33.6 +/- 6.0, p less than 0.05) during the chronic stage. The mean vegetation size was 0.73 +/- 0.30 cm2 in the active stage and decreased to 0.56 +/- 0.24 cm2 (p less than 0.05) in the chronic stage; however, in six of 22 patients (27%), vegetation size did not decrease with clinical cure.(ABSTRACT TRUNCATED AT 250 WORDS)
Myocardial performance after arterial switch operation for transposition of the great arteries with intact ventricular septum.
Authors: Colan S D , Trowitzsch E , Wernovsky G , Sholler G F , Sanders S P , Castaneda A R
Published: June 2011

Left ventricular dimensions, wall thickness, wall stress, and indexes of afterload, preload, contractility, and early diastolic function, as well as regional wall motion, were determined by echocardiographic methods in patients with transposition of the great vessels after arterial switch operation and in age-matched normal controls. In patients evaluated early after surgery, body surface area-adjusted left ventricular dimensions were smaller, and wall thickness was increased compared with controls. Ventricular performance (fractional shortening) was normal in most patients but was abnormally low in 10%. Nevertheless, contractility was normal or augmented in all subjects, with a mean value higher than the control group. The reduction in systolic function was related to altered loading conditions with a combination of reduced afterload and preload combined with augmented contractility. These altered myocardial mechanics appeared to be secondary to routine therapy with digitalis and diuretics. Diastolic function was also normal with differences in the rate of peak filling and rate of wall thinning entirely attributable to differences in ventricular size and function, and normalized indexes of diastolic function were not different between patients and controls. Patients evaluated late after repair were found to have normal regional wall motion with no evidence to suggest regional dysfunction as might be seen with regional ischemia. Ventricular size, wall thickness, systolic function, afterload, preload, contractility, and early diastolic function were indistinguishable from control values. Indexes of diastolic function demonstrated the same relation to age, body surface area, and ventricular size and function in both patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Cine magnetic resonance imaging for evaluation of anatomy and flow relations in infants and children with coarctation of the aorta.
Authors: Simpson I A , Chung K J , Glass R F , Sahn D J , Sherman F S , Hesselink J
Published: June 2011

Sixteen cine magnetic resonance imaging (MRI) studies were performed in 14 patients aged 1 week to 17 years (mean age, 46 months), who had coarctation of the aorta confirmed at angiography or surgery. Conventional echocardiographic-gated MRI was first performed in axial and rotated sagittal views and was used to identify the slice locations for cine MRI. Cine MRI was performed by gradient-recalled acquisition in steady state with a 30 degree flip angle, 12-msec echo time, 22-msec pulse repetition time, and a 128 x 256 acquisition matrix. Coarctation anatomy was extremely well defined in all but one patient who had vascular clips at the coarctation repair site. The smallest descending aortic flow diameter on cine MRI showed excellent agreement with angiography (r = 0.90). Lucent jets of high-velocity flow through the site of coarctation were imaged in eight patients, and jet length correlated well with the angiographic severity of coarctation (r = -0.81). Two patients were restudied after surgery, and they exhibited excellent repair and normal flow patterns. Cine MRI provides high-resolution imaging of coarctation anatomy with a dynamic spatial and temporal visualization of flow and with excellent detail of vascular anatomy and flow both proximal and distal to the coarctation.
Ethanol causes epicardial coronary artery vasoconstriction in the intact dog.
Authors: Hayes S N , Bove A A
Published: June 2011

Ethanol produces in vitro vasoconstriction of coronary arteries and can precipitate angina in patients with coronary obstructive disease. To demonstrate the in vivo effect of ethanol on coronary dynamics, baseline measurements of left anterior descending (LAD) coronary artery dimension by quantitative angiography, hemodynamics, arterial and coronary sinus blood gases, and blood ethanol levels were obtained in 14 closed-chest mongrel dogs. Three ethanol levels were established by intravenous bolus followed by 1-hour maintenance infusions. All measurements made at baseline were recorded every 30 minutes. Phentolamine (5 mg i.v.) and nicardipine (0.15 mg/kg i.v.) were given to evaluate constrictor mechanisms. Blood ethanol levels achieved at 60, 120, and 180 minutes were 649 +/- 48, 1,285 +/- 81, and 2,546 +/- 130 micrograms/ml, respectively. LAD cross-sectional area was reduced significantly from control at the end of each of the three dosing periods (-24 +/- 5%, -40 +/- 3%, and -53 +/- 3%; p less than 0.004). alpha-Adrenergic blockade had no effect on LAD cross-sectional area, while nicardipine partially reversed the ethanol-induced vasoconstriction. No significant change in vessel cross-sectional area took place in control dogs. These data suggest that ethanol induces epicardial coronary artery vasoconstriction in dogs at clinically important blood levels. alpha-Adrenergic blockade does not alter or reverse ethanol-induced vasoconstriction, while calcium channel blockade appears to be an effective vasodilator of ethanol-constricted vessels.
Glutathione redox pathway and reperfusion injury. Effect of N-acetylcysteine on infarct size and ventricular function.
Authors: Forman M B , Puett D W , Cates C U , McCroskey D E , Beckman J K , Greene H L , Virmani R
Published: June 2011

Glutathione peroxidase is an important enzyme in the degradative cascade of reactive oxygen free radicals. N-Acetylcysteine (NAC) is a low molecular weight compound that has been used clinically to replenish glutathione. To assess the role of the glutathione redox pathway on reperfusion injury, 23 animals underwent 90 minutes of proximal left anterior descending coronary artery occlusion followed by 24 hours of reperfusion with the administration of NAC (n = 11) or saline (n = 12) beginning 30 minutes into occlusion and continuing for 3 hours after reperfusion. Regional ventricular function was measured with contrast ventriculography, and regional myocardial blood flow was determined with microspheres. At 24 hours, the area at risk was defined in vivo with Monastral Blue, and the area of necrosis was defined by incubation in triphenyltetrazolium. Biopsies were taken from the ischemic and nonischemic zones to determine levels of total glutathione, superoxide dismutase and glutathione peroxidase activity, and reactivity to thiobarbituric acid, an index of lipid peroxidation. The rate-pressure product and myocardial blood flow were similar in the two groups throughout the study. No significant differences were noted in infarct size expressed as a percentage of the area at risk (28.6 +/- 5.3% vs. 36.6 +/- 6.0%) and of the total left ventricle (14.4 +/- 3.2% vs. 16.5 +/- 3.1%), and no differences were noted between the two groups on examination of the ischemic subendocardium by light and electron microscopy. Both groups exhibited similar degrees of dyskinesis during occlusion; however, treated animals showed significant improvement in regional radial shortening at 3 hours (3.4 +/- 2.4% vs. -2.4 +/- 2.1%, p less than 0.02) and 24 hours (9.2 +/- 2.2% vs. -2.5 +/- 6.3%, p less than 0.001) after reperfusion. No differences were present in total glutathione, thiobarbituric acid reactivity, or superoxide dismutase and glutathione peroxidase activity in the ischemic zones of the two groups. This study suggests that N-acetylcysteine treatment before reperfusion may reduce myocardial stunning but does not limit myocyte death after reperfusion.
Correction for preload in assessment of myocardial contractility in aortic and mitral valve disease. Application of the concept of systolic myocardial stiffness.
Authors: Mirsky I , Corin W J , Murakami T , Grimm J , Hess O M , Krayenbuehl H P
Published: June 2011

With single-beat analysis, the new concept of systolic myocardial stiffness is applied to provide a new approach for the assessment of myocardial contractility in aortic and mitral valve disease. Seventy patients underwent diagnostic right and left heart catheterization. Twenty-six patients had aortic stenosis, 18 had aortic insufficiency, and 26 had mitral regurgitation. Patients with aortic stenosis were divided into two groups on the basis of left ventricular mass index less than 172 g/m2 (AS1) and mass index greater than or equal to 172 g/m2 (AS2). The mitral regurgitation patients were divided into those in normal sinus rhythm (MR1) and those in atrial fibrillation (MR2). Nine patients without significant coronary or cardiovascular disease served as controls. Thirteen patients with aortic stenosis and eight with aortic insufficiency were evaluated (average, approximately 18 months) after successful aortic valve replacement. With simultaneous left ventricular pressure and cineangiographic methods, myocardial contractility was assessed by the conventional ejection fraction-afterload relation (uncorrected for preload) and by two new methods that permit the correction of the ejection fraction for preload. Assessments of the contractile state by these two new methods differed from those by the conventional method in 20-40% of the cases studied. Contractile state improved postoperatively in aortic stenosis and aortic insufficiency even in patients with preoperative depressed contractile states. In patients with mitral regurgitation, there was considerable heterogeneity of contractile function preoperatively. Severe left ventricular hypertrophy in aortic stenosis was not a marker for postoperative outcome since contractility was normal postoperatively in AS1 and AS2 in equal numbers. This study demonstrates that preload correction is important in a preoperative assessment of contractility in aortic and mitral valve disease but that it is less important postoperatively, presumably because of reductions in the preload.