Sequential balloon technique in angioplasty of severe coronary arterial obstructions.
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Angioplasty, Balloon↗
Biomedical subjects
D C Levin
Publications and source records attributed to D C Levin.
Usefulness of transstenotic coronary pressure gradient measurements during diagnostic catheterization.
A difficult problem in coronary arteriography is the assessment of the hemodynamic significance of stenoses that appear angiographically to be of only moderate severity (25 to 75% diameter narrowing). This is particularly important in patients who may be candidates for invasive therapy, such as percutaneous transluminal coronary angioplasty (PTCA) or coronary bypass surgery. To determine the significance of such lesions, we measured transstenotic coronary pressure gradients in 15 patients with angiographically moderate stenoses. For comparison, similar measurements were made in 17 patients with severe stenoses (more than 75% diameter narrowing) being considered for PTCA. The transstenotic pressure gradients were measured with a 2.0Fr polyvinyl chloride catheter cleared of microbubbles of air by flushing with carbon dioxide and degassed saline solution and attached to a low-volume displacement transducer for optimal frequency response. Mean transstenotic pressure gradients greater than 10 mm Hg at rest or more than 20 mm Hg under conditions of high coronary blood flow, as induced by Renografin 76, appeared to be associated with objective evidence of myocardial ischemia and symptomatic relief from PTCA. Smaller pressure gradients occurred in patients whose symptoms probably were not ischemic in nature. Transstenotic pressure gradient determination performed at the time of diagnostic catheterization may provide assistance in clinical decision-making in selected patients with angiographically moderate stenoses.
Angioplasty, Balloon↗
Right heart catheterization in the evaluation of patients with suspected coronary artery disease.
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Cardiac Catheterization↗
Intravenous digital subtraction angiography in diagnosis of vascular graft occlusion.
Differentiation is often difficult between vascular graft occlusion and progression of underlying disease in patients after vascular surgery. We have studied 57 patients after surgery for traumatic and atherosclerotic arterial occlusion and other vascular anomalies using a commercial digital subtraction angiography (DSA) unit; no complications occurred. Indications for examination included pain, diminished pulse, and failure of catheter angiography. Graft patency was established if proximal and distal anastomoses were visualized; occlusion was diagnosed if no graft was imaged or vascular stump found--noted in 31 grafts. Our diagnosis was proved surgically in 24 patients (two refused operation); three others were confirmed angiographically and one by Doppler ultrasonic examination. In our experience DSA is a safe, specific means of following postoperative grafts and diagnosing their occlusion.
Angiography↗
Comparison of intravenous digital subtraction angiography to conventional aortography in patients with abdominal aortic aneurysm.
Evaluation of intravenous digital subtraction angiography (IV DSA) in patients with abdominal aortic aneurysm was performed by obtaining catheter aortograms immediately before DSA studies in ten patients. Diagnostic images were obtained in nine of ten digital subtraction examinations. Although repeat injections were necessary in six DSA and three conventional aortography cases for adequate imaging of both cephalad and caudal extension of the aneurysm, average contrast dose was 53 cc (62 cc in standard catheter studies). Renal artery stenosis was diagnosed by DSA in two of three vessels, multiple renal arteries were demonstrated by both modalities in two cases. Digital subtraction and conventional aortographic findings were proved at surgery. Intravenous DSA was shown to be useful in the preoperative evaluation of patients with abdominal aortic aneurysm.
Angiography↗
Pancreatic masses that angiographically simulate intrasplenic lesions.
Major improvements in the resolving power of computed tomography and ultrasound over the last decade have greatly improved the preoperative evaluation of abdominal masses. Angiography is, however, still often required for vascular mapping and assistance in the differential diagnosis. Although the site of origin of an avascular, intrasplenic mass may be the spleen, our experience and review of the literature indicates that such primary or secondary splenic masses are relatively rare. A primary pancreatic mass often a pseudocyst is a more frequent cause and should figure prominently in the differential diagnosis.
Adult↗
Evaluation of optimized biplane pulmonary cineangiography.
Biplane pulmonary cineangiograms utilizing a short cine pulse width and automatic brightness control were performed in 47 patients during normal respiration. The diagnostic quality of the arteriograms was categorized as good in 33 patients, fair in 12 patients, and poor in two patients. Of the 18 patients in whom pulmonary emboli were identified, cineangiography displayed certain diagnostic features to advantage, including motion of emboli in ten and respiratory scissoring of vessels overcoming vascular superimposition in three. Optimized pulmonary cineangiography is an acceptable alternative to serial film pulmonary angiography for the diagnosis of pulmonary embolism.
Cineangiography↗
Percutaneous transluminal coronary angioplasty with an over-the-wire system.
The original Gruentzig coaxial catheter system for percutaneous transluminal coronary angioplasty (PTCA) utilized a blunt, closed-end, inner balloon catheter with a short guide wire attached to its tip. Options for safely crossing severe stenoses with this large, nonmaneuverable catheter were limited. More recently, over-the-wire systems have been developed in which the lesion initially is crossed with a small-caliber floppy or steerable guide wire, then by the balloon catheter advanced over the wire. Technical success was achieved in 78 of our first 100 PTCAs with this system. Significant cardiac complications occurred in ten patients, seven of whom required emergency coronary bypass surgery. A recently published survey of all PTCA techniques reported a technical success rate of 62%. Our higher success rate may be attributed to certain advantages of the over-the-wire system, which are discussed in detail. A learning curve is associated with this procedure: our success rate was 65% in the first 20 cases but 81% thereafter. These results can be considered typical of those expected at hospitals now beginning PTCA programs with advanced over-the-wire technology.
Angioplasty, Balloon↗
Superselective catheterization of small-caliber arteries with a new high-visibility steerable guide wire.
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Angiography↗
Dissection complicating angioplasty.
Extensive arterial dissection producing significant arterial obstruction or occlusion after technically uncomplicated percutaneous transluminal angioplasty in three patients is described. Despite the initially ominous arteriographic appearance, short-term (4-8 months) follow-up demonstrated complete resolution without surgical intervention. A trial of conservative management is recommended for this complication.
Adult↗
Percutaneous transluminal coronary angioplasty.
Percutaneous transluminal coronary angioplasty (PTCA) has revolutionized the treatment of patients with coronary disease. As many as 25 per cent of those requiring myocardial revascularization can now undergo PTCA instead of bypass surgery. This article reviews PTCA techniques, clinical results, case selection, complications, recent advances in equipment design, restenosis rate, use in acute myocardial infarction, and PTCA of coronary bypass grafts.
Angioplasty, Balloon↗
Percutaneous transluminal angioplasty of the renal arteries.
Percutaneous transluminal angioplasty (PTA) of renal artery stenosis has proved highly efficacious, particularly in patients with lateralizing renal vein renin ratios, fibromuscular dysplasia, and atherosclerotic lesions confined to one renal artery without involvement of the aortic wall surrounding the renal ostium. In some series, a moderate recurrence rate has been reported, but these recurrences usually respond well to redilatation. Complications are relatively rare and generally not serious. Early results compare favorably with those of large surgical series. Some of the disparities in published results of renal PTA may be accounted for by differences in technique. Important advances in both equipment and PTA technique have occurred since the procedure was introduced in 1978; these may prove to favorably affect the long-term results.
Angioplasty, Balloon↗
Equipment choices, technical aspects and pitfalls of percutaneous transluminal angioplasty.
Previously published papers on percutaneous transluminal angioplasty (PTA) have emphasized results rather than techniques. This review deals with equipment choices, technical aspects and pitfalls observed during the first 200 PTAs at the Brigham and Women's Hospital. Specific topics discussed include: (1) catheters kept in stock in the laboratory, (2) choice of approach and entry into the artery, (3) techniques for crossing stenoses, (4) dilatation of the lesion, (5) drugs used during the procedure, and (6) proper performance and interpretation of the postangioplasty arteriogram.
Angioplasty, Balloon↗
Digital subtraction angiography: myths and reality.
Some of the claims made about digital subtraction angiography (DSA) when it was first developed have turned out to be greatly exaggerated, and some members of the radiologic community have become disillusioned with its capabilities. The author discusses some of the limitations of DSA, and concludes that the advantages of DSA outweigh its limitations.
Angiography↗
Cost reduction opportunities in radiology departments.
The recent institution of prospective methods of hospital reimbursement has created a strong incentive to reduce costs. Significant savings were achieved in the cardiovascular-interventional radiology section of our hospital by obtaining competitive bids, purchasing in bulk, purchasing certain comparable but less expensive supplies, reducing film use, and altering patterns of use of some supplies.
Cost Control↗
Contrast agents for cardiac angiography: effects of a nonionic agent vs. a standard ionic agent.
The effects on cardiac hemodynamics and serum parameters of a standard contrast agent (sodium methylglucamine diatrizoate [Renografin 76]) were compared with the effects of a new nonionic agent (iohexol) in a double-blind study in 51 patients undergoing coronary angiography and left ventriculography. No significant alteration in measured blood parameters occurred with either contrast agent. Hemodynamic changes occurred with both, but were significantly greater with the standard Renografin than with the low-osmolality, nonionic iohexol. After left ventriculography, heart rate increased and peripheral arterial pressure fell with both agents, but less with iohexol. Following coronary artery injections, heart rate and arterial pressure decreased with both agents, but the changes were more marked and occurred earlier with the standard contrast material. It is concluded that iohexol causes less alteration in cardiac function than does the agent currently most widely used. Nonionic contrast material is likely to improve the safety of coronary angiography, particularly in those patients at greatest risk.
Angiography↗
Cardiopulmonary hemodynamics during sleep in subjects with chronic obstructive pulmonary disease. The effect of short- and long-term oxygen.
Some patients with chronic obstructive pulmonary disease (COPD) experience transient arterial hypoxemia (TAH) during rapid eye movement (REM) sleep. To examine the effect of short- and long-term low flow oxygen on TAH associated cardiopulmonary hemodynamics, we recorded pulmonary artery pressure (Ppa) and cardiac output during nocturnal sleep in seven male subjects with COPD. In all of the subjects, parameters were measured breathing room air at baseline time and after eight or more weeks of home supplemental oxygen (15 hours per day, 3 L/min). Five were also studied one full night at baseline time while breathing 3 L/min nasal oxygen. While breathing room air both before and after chronic home oxygen therapy, transient increases in Ppa during TAH were due to increased pulmonary vascular resistance in seven instances, increased cardiac output in four, and increases in both vascular resistance and cardiac output in two. Short-term supplemental oxygen lowered mean sleeping Ppa and eliminated TAH along with its associated hemodynamic changes in four of the five subjects; the fifth did not experience REM sleep. In the six subjects who complied with the eight-week home oxygen protocol, mean sleeping Ppa was significantly reduced (p less than 0.05). In four of these, total pulmonary resistance was lower and cardiac output higher after home oxygen therapy. Short-term supplemental oxygen is useful in correcting REM-associated TAH and in some hypoxemic subjects, reducing mean sleeping Ppa. Sustained reductions in pulmonary vascular resistance after long-term home oxygen therapy may be indicative of improved cardiac and pulmonary vascular status even in subjects showing minimal or no reduction in mean sleeping Ppa.
Cardiac Output↗
Evaluating the radiographic assessment of pulmonary venous hypertension in chronic heart disease.
This study evaluated how accurately the chest film could be used to determine pulmonary capillary wedge pressure (PCW) in patients with chronic heart disease. Six experienced readers interpreted the erect posteroanterior chest radiographs of 50 patients whose measured PCWs ranged from 6 to 38 mm Hg. Direct numeric estimates of PCW from the films were closely related to measured levels of PCW (r = 0.675). This linear correlation increased to 0.81 when individual-reader variations were reduced by taking a "consensus" (mean) of the six readers' estimates for each case. A combination of the judged degree of pulmonary blood flow redistribution (PFR) and three particular signs of pulmonary venous hypertension (PVH), basal and perihilar vascular blurring and alveolar edema, adequately summarized the radiographic information about PCW. These combined judgments of PFR/PVH identified films from patients with higher and lower PCW levels as accurately as readers' numeric estimates of PCW. Other radiographic signs (enlargement of the heart and central pulmonary vessels and the presence of Kerley lines or pleural effusion) were also positively related to increases in PCW, but added little to the information provided by the PFR/PVH criteria.
Adolescent↗