Adrian Kantrowitz

Intraaortic balloon pumping for prolonged circulatory support

Prolonged circulatory support with an intraaortic balloon pump (IABP) is controversial, in part because it has not been performed frequently enough to base treatment policy on adequate data. To help clarify this problem, 733 cases of consecutive patients who were supported by IABP between 1967 and 1982 were analyzed. Twenty-seven patients were supported for 20 days or more (range 20 to 71). Twelve (44%) had prior histories of chronic congestive heart failure. Complications were more frequent in prolonged-support patients than in those assisted for less than 20 days (vascular, 37% vs 15%, p = 0.001; infectious, 67% vs 25%, p = 0.0001; and bleeding, 26% vs 15%, p = 0.04, respectively). The survival rate of prolonged-support patients, however, was 63% (17 of 27), essentially the same as that of the controls (57%, p = 0.5). Of 17 prolonged-pumping patients discharged alive from the hospital, 9 died within 6 months but 8 survived greater than 2 years. Among congestive heart failure patients, none was a long-term survivor. Prolonged IABP support in congestive heart failure patients lacking surgically correctable lesions can extend life while arrangements for definitive therapy are made (transplant, permanent mechanical assistance). Where definitive therapy is unavailable, IABP may provide additional months of life.

Long-term stimulation of a diaphragm muscle pouch☆

Abstract Denervated hydraulic pouches were fashioned from a retrosternal portion of the right hemidiaphragm and electrically stimulated for several hours at voltages selected to achieve pressures commensurate with those encountered in the right ventricle. The data revealed a progressive decline in pressures generated by the pouch with time, the deterioration perhaps enhanced by inpaired perfusion of the pouch but statistically independent of systemic blood pressures. Therefore it was concluded that contraction of the diaphragm muscle could not be used clinically to assist the heart.

An Extravascular Left Ventricular Assist Device

The hemodynamic efficacy and prosthesis-vessel interaction of a pneumatically activated circulatory assist device was investigated in 12 acute and 12 chronic studies in dogs. A polyurethane balloon encased in Dacron-velour cloth was fastened to the descending thoracic aorta with a spiral wrapping of Dacron graft material. Diastolic augmentation was provided by rhythmic inflation and deflation of the balloon. Hemodynamic results, based on 5 dogs with experimental myocardial ischemia, showed that left ventricular systolic peak pressure decreased by 8.2 +/- 1.9%, cardiac output increased by 13.1 +/- 2.8%, and circumflex coronary artery flow rose by 17.5 +/- 2.5%. In the chronic experiments the prosthesis was asynchronously but continuously activated from one to sixteen weeks at 74 cycles per minute. Postmortem examination of the implantation site in all 12 dogs showed that necrosis had developed but was limited to the outer half of the medial layer beneath the pumping chamber and that the aortic wall was compressed to about 70% of its original thickness. Although the method described represents a simple form of providing ventricular assistance, its applicability for long-term circulatory support remains to be evaluated.

Simplified Circular Aortotomy in Aortocoronary Bypass Operations to the axis of the aorta.

Abstract Adaptation of a rongeur technique facilitates aortotomy in aortocoronary bypass operations. A single motion with a double-action duckbilled rongeur produces a smooth-walled, symmetrical aortotomy which varies in shape predictably according to the angle at which the rongeur is held relative