TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: With male gender as a strong predictor of cardiovascular instability, we hypothesized that gender-specific differences in circulating carbon monoxide levels contributed to dysregulated microvascular function in preterm male infants.', 'Infants born at 24 to 34 weeks of gestation (N = 84) were studied in a regional tertiary neonatal unit. Carboxyhemoglobin levels were measured through spectrophotometry in umbilical arterial blood and at 24, 72, and 120 hours after birth. Microvascular blood flow was determined through laser Doppler flowmetry.', 'Carboxyhemoglobin levels demonstrated a strong inverse relationship with gestational age (r = -0.636; P < .001) and were higher in boys (P = .032). Repeated-measures analysis of variance showed a significant decrease in arterial carboxyhemoglobin levels over time (P < .001), with significant between-subjects effects for gestational age (P = .011) and gender (P = .025). Positive correlations with microvascular blood flow at 24 hours of age (r = 0.495; P < .001) and 120 hours of age (r = 0.548; P < .001) were observed. With controlling for gestational age, carboxyhemoglobin levels at 72 hours were greater for infants who died in the first week of life (P = .035).\Question: Is carbon monoxide a significant mediator of cardiovascular status following preterm birth?

SOLUTION: The gestational age- and gender-specific differences in carboxyhemoglobin levels and the relationship with dysregulated microvascular blood flow, a state related to greater illness severity and hypotension, are novel findings not confined solely to sick preterm infants. Both inducible heme oxygenase-dependent and non-heme oxygenase-dependent pathways may initially play a central role in carbon monoxide production, inducing pathophysiologic processes in a gender-specific manner.

PROBLEM: Context: We sought to determine whether outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) vary according to CTO target vessel: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA).', 'We evaluated the clinical and angiographic characteristics and procedural outcomes of 636 patients who underwent CTO PCI at 6 high-volume centres in the United States between January 2012 and March 2014.', 'The CTO target vessel was the RCA in 387 cases (61%), LAD in 132 (21%), and LCX in 117 (18%). LCX lesions were more tortuous and RCA lesions had greater occlusion length and Japanese Chronic Total Occlusion (J-CTO) score, but were less likely to have a side branch at the proximal cap and had more developed collateral circulation. The rate of procedural success was lower in LCX CTOs (84.6%), followed by RCA (91.7%), and LAD (94.7%) CTOs (P = 0.016). Major complications tended to occur more frequently in LCX PCI (4.3% vs 1.0% for RCA vs 2.3% for LAD; P = 0.07). LCX and RCA CTO PCI required longer fluoroscopy times (45 [interquartile range (IQR), 30-74] minutes vs 45 [IQR, 21-69] minutes for RCA vs 34 [IQR, 20-60] minutes for LAD; P = 0.018) and LCX CTOs required more contrast administration (280 [IQR, 210-370] mL vs 250 [IQR, 184-350] mL for RCA and 280 [IQR, 200-400] mL for LAD).\Question: Is percutaneous intervention of circumflex chronic total occlusions associated with worse procedural outcomes : insights from a Multicentre US Registry?

SOLUTION: In a contemporary, multicentre CTO PCI registry, LCX was the least common target vessel. Compared with LAD and RCA, PCI of LCX CTOs was associated with a lower rate of procedural success, less efficiency, and a nonsignificant trend for higher rates of complications.

PROBLEM: Context: The purpose of the present study was to evaluate the extent of the ventricular epicardial fat and its relationship with the underlying myocardium, neither of which is still completely understood.', 'A total of 117 autoptic human hearts was subdivided into four groups: normals (N), ischemics (I), hypertrophics (H) and hypertrophic-ischemics (HI). In each heart, the ventricular myocardial and epicardial fat weights were measured. On the basis of these data, the epicardial fat percentage within the ventricles was calculated.', 'The left, right and total ventricular fat weights were greater in H and HI than in N and I (P<.05, P<.05, P<.01, respectively). No differences were detected in the epicardial fat weights in comparing H versus HI and N versus I. Moreover, the fat percentage in each ventricle did not vary between the four groups. However, if compared with the right ventricle, the left ventricle showed an epicardial fat percentage consistently lower (P<.0001). In nonhypertrophied hearts (N and I), the body mass index and the total epicardial fat weight were correlated (P<.05), whereas in hypertrophied hearts (H and HI), they were not.\Question: Is the ventricular epicardial fat related to the myocardial mass in normal , ischemic and hypertrophic hearts?

SOLUTION:
A constant fat-muscle ratio exists in each ventricle, which is not influenced by ischemia or hypertrophy. Accordingly, during the hypertrophic process, the ventricular fat and the underlying myocardium show a parallel and correlated increase in their masses.