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Biomedical subjects

N T Kouchoukos

Publications and source records attributed to N T Kouchoukos.

At least 145 records · Page 8Linked to original sources
PubMed1980

Considerations in selection and management of patients undergoing valve replacement with glutaraldehyde-fixed porcine bioprotheses.

From November, 1973, through June, 1978, 428 operations in 425 patients were performed for replacement of aortic, mitral, or aortic plus mitral valves, utilizing 277 Hancock and 180 Carpentier-Edwards bioprostheses. Actuarially determined survival at 36 months was similar for all three groups and compared favorably with our experience with the Björk-Shiley prosthesis. Certain patient-related variables influencing late survival were identified by multivariate analysis and included previous operation for congenital heart disease, coronary artery bypass grafting in nonaortic valve replacement, race (black), age at operation, and New York Heart Association Functional Class. A small but definite incidence of thromboembolism occurred in all three groups, again similar to our experience with the Björk-Shiley prosthesis. Multivariate analysis identified four factors influencing risk of thromboembolism: previous cardiac operation, age, double-valve replacement, and rhythm at discharge. Valve degeneraation occurred, primarily in children and young adults. Over the medium term, the porcine bioprosthesis compared favorably with mechanical prostheses in terms of survival, function, and thromboembolism. Certain patient-related variables affecting survival may be modified by earlier surgical intervention.

Adolescent↗
PubMed1980

Replacement of the ascending aorta and aortic valve with a composite graft. Results in 86 patients.

We reviewed our entire experience with composite graft replacement of the ascending aorta and aortic valve during a 63 month interval ending in December, 1979. Anuloaortic ectasia was the most common indication for operation, followed by aortic dissection (acute and chronic). Hospital mortality was 5% and was related to the preoperative functional status and the duration of intraoperative myocardial ischemia. Reoperation on the ascending aorta for reasons other than postoperative hemorrhage was required in five of the 82 hospital survivors (6%). By actuarial analysis, 90% of hospital survivors were free of any reoperation on the ascending aorta or aortic valve three years postoperatively, and 93% were free of reoperation related specifically to the composite graft. Pseudoaneurysms at the coronary ostia or distal aortic anastomosis were observed in five of 16 patients having postoperative angiography. One of the five patients has required reoperation. Follow-up has averaged 23.5 months (range: 0.2-60 months). Three year actuarial survival for the 86 patients was 81%, for 44 patients with anuloaortic ectasia was 88%, and for 31 patients with aortic dissection was 83%. Composite graft replacement of the ascending aorta and aortic valve is a satisfactory alternative to supracoronary graft replacement and aortic valve replacement. It offers the advantage of excluding all aneurysmal tissue from the aortic anulus to the innominate artery, thereby eliminating the potential for later development of aneurysms of the sinuses of Valsalva, a known complication of the supracoronary technique. It is the method of choice for patients with anuloaortic ectasia and cephalad displacement of the coronary ostia. It is suitable for many patients with acute or chronic dissection and for patients with sinuses of Valsalva aneurysms following previous operations on the ascending aorta or aortic valve.

Adolescent↗
PubMed1980

Hemodynamics during diazepam induction of anesthesia for coronary artery bypass grafting.

The hemodynamics during induction of anesthesia were studied in ten patients with ischemic heart disease about to have coronary artery bypass grafting. Intravenous diazepam, 0.5 mg/kg (with 50% N2O in oxygen inspired and pancuronium IV), was used to induce anesthesia. Compared to awake baseline, induction caused statistically significant decreases in the mean arterial pressure, rate pressure product, stroke index, and left and right ventricular stroke work indexed. Although statistically significant, the hemodynamic changes were small and transient and required no modifying treatment. This anesthetic induction technic is safe, efficient, and well tolerated by patients having myocardial revascularization surgery.

Anesthesia, General↗
PubMed1979

Unstable angina pectoris: a comparison of the costs of medical and surgical treatment.

This study compares the inpatient costs of therapy of patients with unstable angina pectoris randomized to surgical or medical therapy at the University of Alabama in Birmingham as part of the National Cooperative Study Group. For 74 patients followed up for 2 years, the mean inpatient charges were $4,728 for 22 medically treated patients, $9,528 for 34 surgically treated patients and $20,215 for 18 patients who crossed over from medical to surgical therapy. Differences among the three groups were statistically significant (P less than 0.001). Stepwise multiple regression analysis of total inpatient charges with medical and procedural factors as explanatory variables showed that a history of congestive heart failure, the number of infarctions during the period of the study, the duration of the longest anginal attack, the type of unstable angina and the type of treatment were significant predictors of total inpatient cost, with an R2 value of 0.829 (P less than 0.001). These variables explain the cost of treatment. One should not infer that they will also predict the appropriate type of treatment for patients with unstable angina. Although the cost of surgical therapy was double the cost of therapy for patients treated only medically, those medically treated patients whose therapy failed and who subsequently required surgery incurred mean costs twice those of the surgically treated patients and four times of patients who received only medical therapy. Reassessment of previous criticism of the high cost of surgical therapy is indicated.

Aged↗
PubMed1979

Surgical repair of dissection of the upper descending thoracic aorta and discrete ascending aortic aneurysm.

This report describes successful staged surgical repair in 2 patients with dissection of the upper descending thoracic aorta (DeBakey type III) with coexisting discrete Marfan's aneurysms of the ascending aorta. Initial repair of the descending aortic dissection was done through a left thoracotomy using a transverse aorta--femoral artery shunt in 1 patient and a left ventricular apex--femoral artery shunt without systemic heparinization in the other. Emphasis is placed on the need for pharmacological reduction of blood pressure during aortic cross-clamping as well as the use of a shunt to prevent dissection of the ascending aortic aneurysm. In both patients, subsequent repair of the ascending aortic aneurysm was accomplished using composite graft replacement of the aortic valve and ascending aorta. This operation is advised for such patients even in the absence of notable aortic valve incompetence.

Adult↗
PubMed1979

Combined aortic valve replacement and myocardial revascularization: results in 220 patients.

During a 7.5-year period ending in June 1977, 220 patients underwent combined aortic valve replacement and myocardial revascularization. Early (30-day) mortality was 5.4% (12 patients), and was significantly affected by the development of perioperative myocardial infarction. For 23 patients with electrocardiographic and enzymatic evidence for definite infarction, hospital mortality was 17%; for 66 patients with probable infarction mortality was 5%; and for 116 patients without evidence for infarction mortality was 3%. The difference in mortality between the definite and no infarction groups was significant (p less than 0.01). The incidence of perioperative infarction was influenced by the type of myocardial protection employed during the operative procedure. Definite infarction occurred in 24% of 41 patients who had mild (28-32 degrees C), intermittent hypothermic coronary perfusion, in 9% of 142 patients with hypothermic ischemic arrest (myocardial temperature 20 to 27 degrees C) and in none of 22 patients with hypothermic, potassium-induced cardioplegia (myocardial temperature 8--18 degrees C). The difference in the rate of infarction between the coronary perfusion and the two hypothermic ischemic arrest groups was significant (p less than 0.01). The mean duration of followup for 100% of the hospital survivors was 22.5 months. Cumulative survival was 88% at 1 year and 77% at 3 years. These figures do not differ significantly from those for patients without coronary artery disease having isolated aortic valve replacement in our institution, and are superior to those reported for patients with coronary and aortic valve disease undergoing only aortic valve replacement. We conclude that combined aortic valve replacement and myocardial revascularization should be performed in all patients in whom the lesions coexist. Hypothermic ischemic arrest, preferably in combination with potassium-induced cardioplegia, provides the most myocardial protection during operation.

Adult↗
PubMed1979

Unstable angina pectoris: an examination of modes and costs of therapy.

Debate exists over the most appropriate form of treatment for patients with unstable angina pectoris. This study examined 106 patients randomized at the University of Alabama in Birmingham as part of the National Cooperative Study Group and focuses on the phenomenon of patients who fail medical therapy and thus require late surgery, and the costs of therapy. Discriminant function analysis revealed that the significant predictors (p less than 0.01) of patients who would later require surgery were: total number of vessels diseased, angina severly, presence of congestive heart failure, hypertension, and number of years that the patient had had angina. By means of this analysis, 85% of the late surgery patients were correctly predicted. Late surgery patients averaged 2.4 diseased vessels vs 1.5 for persistent medical patients (p less than 0.01). Mean charges for the first 2 years in the study were $6,226 (SD $2,967) for persistent medical patients, $10,416 (SD $2,146) for surgery patients, and $20,059 (SD $10,748) for late surgery patients (p less than 0.001). These data indicate that surgery is clearly an expensive procedure; but that it is more expensive for late surgery patients, who have total costs that are twice as high as surgical costs and 3.5 times as high as persistent medical costs.

Alabama↗
PubMed1979

Research related to surgical treatment of coronary artery disease.

In the past 20 years, basic and clinical research have provided new information on coronary artery surgery. For example, several studies have shown that coronary artery bypass grafting is more effective than medical treatment in relieving the symptoms of chronic disabling angina pectoris. However, we still do not have definitive answers to many questions. What factors in the patient, in the operation and in the care after operation determine success in surgical treatment? Does the operation prolong useful life? Is the operation affordable? These questions are difficult. Further research is needed to solve complex problems relating to surgical vs medical treatment of coronary artery disease.

Adult↗
PubMed1979

Hemodynamic effects of aortic clamping and decompression with a temporary shunt for resection of the descending thoracic aorta.

To assess the effects clamping of the proximal thoracic aorta and of subsequent decompression with a temporary shunt on cardiac function during resection of aneurysms of the descending thoracic aorta, mean arterial (MAP), central venous (CVP), mean pulmonary arterial (MPAP), and pulmonary capillary wedge pressures (PCWP), as well as cardiac index (CI), were measured in eight patients at baseline, 2 minutes after clamping the aorta beyond the left carotid or left subclavian artery, and 2 minutes after opening the shunt. Following clamping, MAP, CVP, and PCWP increased significantly (P less than 0.05), while CI decreased significantly, an average of 29%, and heart rate remained unchanged. After opening the shunt, all pressures returned to baseline levels. CI increased, but remained below the baseline level in seven of the eight patients (P less than 0.05). Our data indicate that significant deterioration of left ventricular performance results from clamping and that the deleterious effects can be reversed by use of a temporary shunt. They support the recommendation of proximal aortic decompression during thoracic aneurysmectomy.

Adult↗
PubMed1978

Primary repair of complete atrioventricular canal in patients less than 2 years old.

Twenty-seven consecutive patients less than 2 years of age underwent primary intracardiac repair of complete atrioventricular (A-V) canal. Three (19 percent) of the 16 operated on after January 1, 1975 died in the hospital, a smaller proportion than the 8 of 11 patients who died in the hospital after operation between 1972 and 1975 (P = 0.005). The date of operation as a continuous variable is also related to the probability of hospital death (P = 0.016). Age at operation was not related to hospital mortality among the total group of 27 infants, nor were the anatomic characteristics of the anterior and posterior bridging leaflets, the location and size of the interventricular communications or the duration or technique of profound hypothermia (total circulatory arrest versus low perfusion flow rate). The improved results in the 16 patients operated on since January 1, 1975 are believed to be primarily the result of an improved ability to construct "mitral" and "tricuspid" valves from the common A-V valve. Fourteen of the 16 hospital survivors are alive and well 5 to 60 months after operation. These results and the natural history of patients with this malformation indicate that there should be no change in the policy of performing elective intracardiac repair before age 2 years and primary repair rather than pulmonary arterial banding when operation is required in the early months of life.

Age Factors↗