Angioscopy Is Useful In The Evaluation Of Chronic Pulmonary Arterial Obstruction

Angioscopy is useful in the evaluation of chronic pulmonary arterial obstructionDeborah ShureGabriel GregoratosKenneth M. MoserUniversity of California, San Diego, School of MedicineDepartment of MedicineAbstractWe have previously described a fiberoptic angioscope for diagnostic use in the rightheart and pulmonary arteries. The instrument has a 4 mm O.D., a proximal flexion controllever, and a 0.8 mm inner channel used to inflate a polyurethane balloon attached to thedistal end of the instrument. A conventional xenon light source provides illumination.The instrument is inserted through a right jugular venotomy and passed into the right heartand pulmonary arteries using direct vision and fluoroscopic guidance. The procedure hasbeen performed in 4 patients with pulmonary hypertension suspected to be caused by chronicpulmonary emboli. Chronic emboli were found in two patients and central (resectable) embolicould be distinguished from peripheral ones. The third patient had normal pulmonary arter-ial intima and a final diagnosis of primary pulmonary hypertension was made. The fourthpatient had extrinsic compression of pulmonary arteries by enlarged mediastinal nodessecondary to fibrosing mediastinitis. No complications occurred. We conclude that angio-scopy appears to be useful in the diagnostic evaluation of patients with suspected chronicobstruction of the pulmonary arteries.IntroductionWe initially described the ability of fiberoptic angioscopy to visualize acute pulmo-nary emboli in animals using a modified pediatric bronchoscope and a latex balloon to dis-place blood from the structures to be viewed.' We subsequently demonstrated improved opti-cal capability using a prototype fiberoptic angioscope and a clear polyurethane balloon.2In this same study, we found that angioscopy could accurately identify the location ofacute pulmonary emboli in animals in vessels 4 mm or larger in internal diameter. Thetechnique gave more anatomically accurate information than radionuclide lung perfusionscans which tended to provide functional information on the distribution of blood flow. Wehave also addressed the issue of the physiologic effects of angioscopy in animals and havfound it to be a safe procedure even in the presence of extensive acute pulmonary emboli.In this study, we report on the use of this technique in adult humans with pulmonaryhypertension suspected to be caused by chronic pulmonary emboli. Chronic emboli are bloodclots in the lung which do not undergo the normal process of clot lysis and resolution.They remain in the vessel and eventually form firm, rubbery masses which become adherent tovessel walls and cause obstruction. With time the vessels may partly recannalize. As aresult of this process, chronic emboli create unusual and varied images with conventionaldiagnostic imaging techniques such as lung perfusion scan and angiography. In addition,only clots located in the central pulmonary arteries are surgically accessible and thiscentral region is the most difficult to access with currently available imaging procedures.Because of these difficulties with current diagnostic techniques, we chose suspectedchronic emboli as the initial focus of our evaluation of the diagnostic capabilities ofangioscopy in humans.MethodsInstrumentA prototype angioscope manufactured by the Machida Corporation was used. The designof the instrument is the same as that of a conventional fiberoptic bronchoscope, but thedimensions are different. The angioscope bundle is 80 cm long with an external diameter of