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Biomedical subjects

L H Cohn

Publications and source records attributed to L H Cohn.

At least 271 records · Page 15Linked to original sources
PubMed1976

Aortic valve replacement with the Hancock porcine xenograft.

The Hancock porcine xenograft stabilized with the glutaraldehyde process was used for isolated aortic valve replacement in 71 patients from March, 1972, to July, 1975. Aortic stenosis was the primary diagnosis in 52 patients and aortic insufficiency in 19. There were 52 men and 19 women ranging in age from 18 to 82 years; 14 patients were older than 70 years. One patient was in Functional Class II, 50 in Class III, and 20 in Class IV preoperatively. Seventy-three patients undergoing Björk-Shiley aortic valve replacement during the same period are presented for comparison. The operative mortality was 3% (2 of the 71 patients); 4 of the remaining 69 patients (6%) died in the late postoperative period. No patient was placed on anticoagulation during the postoperative course, and there was 1 postoperative embolus in a patient with chronic atrial fibrillation (1.4%). With a mean follow-up period of 17 months, 60 patients are now in Functional Class I, 4 in Class II, and 1 in Class III. Seven patients have had transvalvular gradients and effective valve areas measured postoperatively that ranged from 32 to 5 mm Hg and 0.9 to 2.9 cm2 in 21 through 25 mm (OD) sizes.

Adolescent↗
PubMed1976

Actuarial comparison of Hancock porcine and prosthetic disc valves for isolated mitral valve replacement.

From July 1970 through December 1974, 109 patients underwent isolated mitral valve replacement (MVR). A Harken prosthetic disc valve (DVR) was used in 53 patients and glutaraldehyde-preserved Hancock porcine xenograft (PVR) in 56 patients. The functional class, distribution of mitral valve pathology, and incidence of atrial fibrillation were similar in both groups. There were no operative and three (5.5%) late deaths in the PVR group and two (3.8%) operative and ten (19.5%) late deaths in the DVR group. Anticoagulants were not used in the PVR group; there were 3 nonfatal emboli (10%), all occurring in patients with atrial fibrillation and large left atria. Although anticoagulants were used there were 14 emboli (five in patients who died, nine nonfatal) in the DVR group (26.4%). In our experience, there is a significant reduction in morbidity and mortality, primarily from a reduced risk of thromboemboli, if a porcine valve is used for MVR. Anticoagulants should be used in patients with atrial fibrillation and enlarged left atria regardless of the type of valve used.

Adult↗
PubMed1976

Use of the augmented ejection fraction to select patients with left ventricular dysfunction for coronary revascularization.

Thirty-three patients with angina (31 men and 2 women, age 33 to 68 years, 52), as well as signs and symptoms of severe left ventricular dysfunction, were evaluated for coronary revascularization surgery. All had multiple vessel coronary artery disease and at least one prior myocardial infarction. Cardiac catheterization demonstrated abnormally elevated left ventricular end-diastolic pressure (LUEDP), low cardiac output, and depressed resting biplane systolic ejection fraction (SEF) ranging from 18 to 45 per cent (31 per cent). To evaluate potential myocardial function, a premature ventricular contraction was introduced during the ventriculogram and the SEF of the postextrasystolic potentiated (PESP) beat calculated and compared to a sinus beat SEF. Patients were separated into two groups based on the increase in SEF: those with greater than 0.10 augmentation (24 patients) and those with less than 0.10 augmentation (9 patients). Coronary revascularization was carried out with at least two bypass grafts in each patient. The operative mortality in those with more than 0.1 SEF augmentation was 9 per cent (2/24), late mortality rate 5 per cent (1/22), and 20/21 became Class I or II in the follow-up period of 11 to 57 months (25). Operative mortality in those with SEF augmentation of less than 0.1 3/9 33 per cent), late mortality rate 1/6, and only 1/5 achieved Class 1 status during the follow-up period of 10 to 35 months (22) postoperatively. These data suggest that significant augmentation of SEF by a premature ventricular contraction is a simple and useful indicator to aid in selection of patients with left ventricular dysfunction for coronary revascularization.

Adult↗
PubMed1975

Coronary artery anatomy before and after direct revascularization surgery: clinical and cinearteriographic studies in 67 selected patients.

This report relates the postoperative clinical and cineangiographic status of 67 patients selected from a total of 202 patients who underwent coronary artery surgery at the Peter Bent Brigham Hospital from July, 1970, to July, 1972. The mean interval after operation was 12.6 months. Ninety-one per cent of the 67 patients were improved from their preoperative status. Forty-eight patients (71 per cent) were studied to evaluate recurrence of mild to moderate angina or occurrence of interval myocardial infarction, and 19 patients (29 per cent) were entirely asymptomatic. In the 67 patients studied, 112 coronary arteries received a total of 115 grafts. (There were 89 ungrafted coronary arteries.) Total graft patency rate for the 58 patients in whom angina was totally or significantly relieved was 65 per cent. However, one or more grafts were patent in 52 (90 per cent) of these 58 patients. In grafted arteries, progression was found in segments proximal to the graft in 37 per cent of arteries, at the site of anastomosis in 10 per cent, and distal to the site of anastomosis in 17 per cent. The frequency of obstruction distal to the site of anastomosis was not significantly different from the frequency of progression in nongrafted arteries, in contrast to preliminary data from this laboratory. Overall and regional progression in grafted arteries appeared to occur primarily within the first four months after surgery and was found, thereafter, in a constand percentage of vessels studied. Progression in coronary arteries was independent of patency or occlusion of the graft to the vessel. It is hypothesized that while proximal progression is probably a consequence of altered hydraulic factors, distal lesions seem to represent natural progression of atherosclerotic disease.

Angina Pectoris↗
PubMed1975

Improved long-term survival after aortocoronary bypass for advanced coronary artery disease.

Three hundred thirty patients undergoing coronary bypass grafts for disabling angina, "preinfarction" angina, or coronary occlusion without cardiogenic shock have undergone coronary revascularization from July 1970 to March 1974. The operative mortality was 1.2 per cent and the long-term mortality, 4 per cent. Patients were subjected to life table analysis, and the figures suggest that in patients with two- and three-vessel coronary artery disease who received complete revascularization, there was a significant prolongation of life when compared with data from a large series of medically treated patients with angiographically documented coronary artery disease. Longer follow-up data will be important in definitively ascertaining the favorable effect of coronary revascularization on longevity.

Adult↗
PubMed1975

Cardiac surgery in patients undergoing renal dialysis or transplantation.

The coexistence of organic cardiac disease and chronic renal failure presents a therapeutic dilemma. Cardiac operations have been performed on patients who were undergoing hemodialysis or who had had successful renal transplantation. There are several aspects of management of these patients which differ from those of the routine cardiac surgical patient. Guidelines for management are outlined and discussed.

Adult↗
PubMed1975

Local cardiac hypothermia for myocardial protection during correction of congenital heart disease.

Eighty-eight operations for correction of intracardiac congenital heart defects were performed using local cardiac hypothermia for protection of the ischemic myocardium. Twenty-six patients underwent repair of tetralogy of Fallot, 23 had patch closure of ventricular septal defect, 24 had correction of various types of congenital aortic stenosis, and 15 were operated upon for other complex lesions. The overall operative mortality was 5.6%. Ischemia times ranged from 9 to 119 minutes (mean, 48 minutes). Ischemic arrest protected by local cardiac hypothermia provides an optimal operative field, permitting repair of uncomplicated intracardiac defects in a precise, unhurried manner. No hemodynamic abnormalities attributable to the technique were encountered.

Adolescent↗
PubMed1975

Relation between contractile reserve and prognosis in patients with coronary artery disease and a depressed ejection fraction.

Postextrasystolic potentiation (PESP) and 1-epinephrine infusion have previously been shown by the ventriculographic technique to augment left ventricular wall motion in patients with coronary artery disease. The present study relates the magnitude of this augmentation to short-term prognosis in 56 patients with coronary artery disease and a factor already identified with reduced life expectancy, i.e., an abnormal ejection fraction (EF less than .50). Forty-two patients received PESP and 14 1-epinephrine infusion. Based on severity of symptoms and technical suitability, 37 were treated surgically and 19 medically. Mean follwo-up times were 11.7 and 14.3 months, respectively. The mean increase in EF induced by PESP or 1-epinephrine infusion was significantly greater in patients who subsequently had good results from either surgical or medical therapy than in those who died or had progressive cardiac deterioration. In addition, those patients with an increase in EF of .10 or greater had a statistically greater chance of doing well than patients with less augmentation. Evaluation of change in ejection fraction after inotropic stimulation in patients with depressed ejection fractions is helpful in identifying those patients with greatest contractile reserve and hence better short-term prognosis with eigher medical or surgical therapy. Because of its ease of performance and greater enhancement of contractility, PESP is preferred to 1-epinephrine infusion as the inotropic stimulus of choice.

Cardiac Catheterization↗
PubMed1975

Ventricular function before and after direct revascularization surgery. A proposal for an index of vascularization to correlate angiographic and ventriculographic findings.

In order to determine the effect of direct bypass surgery on the total coronary arterial supply to the heart, a numerical construct was devised to incorporate the development of new obstructive lesions and the presence of patent or nonpatent grafts. This construct, termed a vascularization index (VI), was used to evaluate left ventricular function and anginal symptoms after coronary artery bypass surgery in 56 patients. Patients with an increase in local or total arterial blood supply (positive delts VI) often had similar directional changes in segmental wall motion and ventricular ejection fraction. Patients with a decrease in local or total arterial blood supply (negative delta VI), due to either nonpatent grafts or progression of atherosclerotic disease, also usually had similar directional changes in segmental wall motion and ventricular ejection fraction. (Although nearly all patients reported a decrease in anginal symptoms after surgery, delta VI could not identify degree of improvement.) Use of an integrated approach in describing pre and postoperative myocardial blood supply appears to be the most reliable method of explaining changes in left ventricular function.

Angiocardiography↗
PubMed1975

Cardiac valve replacement with the stabilized glutaraldehyde porcine aortic valve: indications, operative results, and followup.

Porcine aortic valve xenografts stabilized with glutaraldehyde have been implanted in 91 patients with acquired and congenital valvular heart disease. The indications for use of this valve have included age, previous sensitivity to anticoagulants, or a concomitant condition contraindicating anticoagulant therapy. There were two operative deaths and three late deaths in 44 mitral, 25 aortic, 16 aortic-mitral, 5 mitral-tricuspid, and one aortic-mitral-tricuspid replacements. There were no valve failures from cusp rupture, although one valve was replaced because of annular disproportion. There was one inhospital stroke but no late emboli in a 3 to 33 month followup period, 16.5; 72 patients are functional class 1, 10 class 2, and one patient is class 3. In appropriate patients this biologic tissue valve relieves the hemodynamic abnormalities of valvular heart disease, is associated with a low embolization rate without anticoagulant therapy and, to date, has been durable.

Adolescent↗
PubMed1975

The effects of phlebotomy, hemodilution and autologous transfusion on systemic oxygenation and whole blood utilization in open heart surgery.

Blood utilization in 400 consecutive adult patients undergoing a wide variety of cardiovascular operations requiring cardiopulmonary bypass was documented following institution of: 1) complete oxygenator hemodilution; 2) intraoperative phlebotomy and autologous transfusion; 3) infusion of residual oxygenator red cells; and 4) use of reconstituted frozen cells in patients whose blood type was uncommon. These techniques have resulted in an average utilization of 4.8 units of blood per adult patient. Fourteen patients required no blood at all and a total of 259 patients required less than 5 units of blood during their entire hospital course. Physiologic effects of this blood program and hemodilution were evaluated in ten patients and the results indicate that marked reduction of red cell mass by hemodilution with hypothermia and low flow perfusion is not detrimental to satisfactory whole blood oxygenation during open heart surgery.

Adolescent↗
PubMed1975

Determinants of survival following cardiac operations in elderly patients.

Ninety-four cardiac operations were performed on 92 patients 65 years of age and over at the Peter Bent Brigham Hospital, Boston, from July 1970 to July 1974. There were 39 aortic valve replacements, 11 mitral valve replacements, 14 double valve operations, 16 coronary revascularizations, five repairs of aortic dissections, and one atrial septal defect closure. The operative mortality was 11 percent in elective cases and 40 percent in the emergency cases, an overall mortality of 17 percent. There were no hospital deaths following elective double valve operations or coronary bypass procedures. Combined hospital and late mortality of ventricular aneurysmectomy approached 100 percent. Myocardial infarction accounted for eight of the 16 hospital deaths. The overall late mortality has been 7.5 percent. Ninety-seven percent of surviving patients are functional class 1 or 2 with a follow-up of 4 to 48 months. These data suggest that any necessary cardiac surgery, excepting ventricular aneurysmectomies, may be performed electively with low risk and a high likelihood of satisfactory rehabilitation in the elderly age group. The major determinants of mortality are the urgency of the intervention and associated coronary artery disease.

Aged↗