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Biomedical subjects

N T Kouchoukos

Publications and source records attributed to N T Kouchoukos.

At least 109 records · Page 6Linked to original sources
PubMed1986

Management during reoperation of aortocoronary saphenous vein grafts with minimal atherosclerosis by angiography.

The proper management of saphenous vein grafts showing minimal angiographic evidence of atherosclerosis at the time of reoperation for progressive atherosclerosis in the native coronary circulation or for severe atherosclerosis in other saphenous vein grafts is uncertain. Following the occlusion of vein grafts in 2 patients 7 and 12 years after operation but only 2 years after arteriography demonstrated no major abnormalities in the grafts, we adopted a policy of elective replacement of all saphenous vein grafts, irrespective of angiographic findings, when reoperation was necessary 5 or more years after the initial operation. Between July, 1984, and May, 1985, 16 patients had repeat coronary artery bypass grafting 6 to 13 years (mean, 9 years) after the initial procedure. Complete revascularization was carried out in all patients. In each, it included replacement of at least 1 saphenous vein graft showing no severe obstruction (less than 30% of the luminal diameter) and no (5 patients), minimal (8), or moderate (3) luminal irregularities by angiography. By pathological examination, 3 of the grafts had minimal, 5 had moderate, and 8 had severe atherosclerotic changes present. These changes were generally more diffuse than those observed by angiography. Because angiography underestimates the severity of the atherosclerotic degeneration in saphenous vein grafts and because of the propensity of the atherosclerotic disease to progress at an unpredictable rate, we recommend routine replacement of all saphenous vein grafts at the time of reoperation if done 5 or more years after the initial procedure.

Adult↗
PubMed1986

Combined bipolar dual chamber pacing and automatic implantable cardioverter/defibrillator.

A 67 year old man with recurrent hypotensive ventricular tachycardia, amiodarone-induced bradyarrhythmias and severe cardiac dysfunction underwent simultaneous implantation of an automatic cardioverter/defibrillator and bipolar atrioventricular (AV) pacemaker. The pacing electrodes were placed epicardially near the right atrial appendage and on the lateral right ventricular wall. The rate detector of the automatic defibrillator was placed epicardially on the posterobasal left ventricular wall. Effective bipolar AV pacing produced no false counting of the heart rate by the automatic cardioverter/defibrillator, and ventricular tachycardia properly inhibited the pacemaker. Long-term follow-up study confirmed the safety of this treatment. With proper precautions, bipolar AV pacing can be safely combined with an automatic cardioverter/defibrillator.

Aged↗
PubMed1986

Eleven-year experience with composite graft replacement of the ascending aorta and aortic valve.

Between September, 1974, and December, 1985, 127 patients had replacement of the ascending aorta and aortic valve with a composite graft. Annuloaortic ectasia was the most common indication for operation (69 patients), followed by aortic dissection (51 patients). Twenty-four patients (19%) had the Marfan syndrome. Hospital mortality was 4.7%. Emergent operation for acute dissection was the only independent predictor of hospital death (p = 0.03). Reoperation for postoperative hemorrhage was required in 15 patients (11.8%) and for prosthesis-related complications (pseudoaneurysm, prosthetic endocarditis, technical problems, and valve thrombosis) in 16 patients (12.6%). Since we adopted a technique of preclotting the prosthesis with whole blood or albumin plus autoclaving and abandoned the inclusion technique, the reoperation rate has declined substantially. At 5 years, the actuarial freedom from reoperation for any reason on the ascending aorta or aortic valve for the 24 patients in whom this modification was used was 90% and for the remaining 103 patients, 73% (p = 0.17). No reoperations for pseudoaneurysms or technical problems were required in these 24 patients, whereas 10 reoperations for these complications were necessary in the other patients. The mean duration of follow-up was 54 months. The actuarial survival rate at 7 years for the entire group was 65%; for the patients with annuloaortic ectasia, 70%; for those with aortic dissection, 61%; for the patients with the Marfan syndrome, 57%. Actuarial freedom from operation on the remainder of the aorta at 7 years was 89%, but it was 78% for the subgroup with the Marfan syndrome. The satisfactory results with extended follow-up support the continued use of the composite graft technique as the preferred method of treatment for patients with annuloaortic ectasia or recurrent aneurysms of the sinuses of Valsalva and for patients with aortic dissection who require aortic valve replacement.

Actuarial Analysis↗
PubMed1985

Morbidity and mortality of coronary bypass grafting in patients 70 years of age and older.

The hospital mortality and major factors contributing to hospital morbidity and postoperative length of stay were examined in 597 consecutive patients 70 years of age and older who underwent isolated coronary artery bypass grafting (CABG) between January, 1978, and December, 1983. The mean age of the patients was 73 years, and 66% were men. Unstable angina was present in 59% of patients, left main coronary disease in 13%, and moderate or severe left ventricular dysfunction in 10%. The mean number of arteries grafted per patient was 3.4. The hospital mortality was 2.7% (16 patients) and was higher than the mortality among 4,125 patients less than 70 years of age (0.4% in 18 patients) operated on during the same interval (p less than 0.001). In multivariate regression analyses, age of 80 years or greater, evolving myocardial infarction, serious coexisting illness, major left ventricular dysfunction, emergent operation, and the development of major postoperative complications were significant (p less than 0.05) independent predictors of increased hospital mortality. Major complications occurred in 135 patients (23%). In multivariate analyses, the presence of vascular disease, serious concomitant illness, and the need for urgent or emergent operation were significant independent predictors of the development of major postoperative complications. The mean duration of postoperative hospital stay was 10.6 +/- 6 (standard deviation) days. In multivariate analyses, the development of major postoperative complications was the only variable independently predictive of prolonged hospital stay. With current techniques, CABG procedures can be safely performed in the elderly with mortality and morbidity rates only slightly higher than those in younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Late results of surgical and medical therapy for patients with coronary artery disease and depressed left ventricular function.

Late survival and freedom from myocardial infarction were determined for 192 patients with coronary artery disease and depressed left ventricular ejection fraction at rest (less than or equal to 35%) determined by biplane angiography who were evaluated between 1970 and 1977. Seventy-seven patients had coronary artery bypass grafting and 115 patients were treated medically and were considered surgical candidates. The medical and surgical groups were comparable in all baseline characteristics examined except frequency of three vessel disease and angina pectoris, which occurred in a significantly greater percent of the surgically treated patients (p less than 0.01). Only three medically treated patients (2.6%) underwent coronary bypass grafting in the follow-up period. Seven year actuarial survival was 63% in the surgical and 34% in the medical group (p less than 0.001). Ninety-three percent of patients in the surgical group and 81% of those in the medical group were free of nonfatal myocardial infarction (p = 0.01), and 62 and 33%, respectively, were alive and free of myocardial infarction (p less than 0.001) at 7 years. Significant differences in survival favoring surgical treatment were observed for the subsets of patients with an ejection fraction of 25% or less (p = 0.0002) and 26 to 35% (p = 0.01), and for the subsets with three vessel coronary disease (p less than 0.001), normal left ventricular end-diastolic volume (less than or equal to 100 ml/m2) (p = 0.005) and elevated end-diastolic volume (greater than 100 ml/m2)(p = 0.001). After adjustment for other important prognostic variables, the type of treatment remained significant in predicting the relative risk (medical to surgical) of mortality at 5 and 7 years (2.58 and 2.12, respectively). These data corroborate the trends observed in several randomized trials of medical and surgical therapy in patients with abnormal left ventricular function. If hospital mortality for coronary artery bypass grafting is less than 5%, substantial benefit can be anticipated for the majority of patients with depressed ventricular function.

Cardiac Volume↗
PubMed1984

Hydroxyethyl starch versus albumin for colloid infusion following cardiopulmonary bypass in patients undergoing myocardial revascularization.

Hydroxyethyl starch or hetastarch (HES), a synthetic colloid for intravascular volume expansion, was compared with albumin after coronary artery operations in 30 patients (15 in each study group). Cardiac index, atrial pressures, heart rate, and systolic blood pressure were similar in both groups. There were no differences in cumulative urine output at 24 hours or in weight change during the first 7 postoperative days. Values for colloid osmotic pressure, as well as for this variable minus left atrial pressure, were lowest soon after bypass but returned to baseline within 4 hours, with no difference between groups in the first 24 hours or 7 days after operation. Coagulation variables were similar, but prothrombin and partial thromboplastin times were higher 12 hours postoperatively and fibrinogen level was lower 7 days postoperatively in the patients receiving HES. There was no clinical evidence of excessive bleeding, although cumulative chest drainage at 12 and 24 hours was slightly higher in the HES group (p = 0.09 and 0.08, respectively). We conclude that hetastarch is a safe and effective colloid to use following coronary operations.

Albumins↗
PubMed1984

Early results of valve replacement with the Björk-Shiley convexoconcave prosthesis.

The Björk-Shiley convexoconcave prosthetic valve has design characteristics that may result in a lower incidence of thromboembolic complications than the conventional spherical Björk-Shiley prosthesis. We evaluated the results of valve replacement with the convexoconcave prosthesis in 248 patients receiving 301 prosthetic valves between March, 1979, and June, 1981. One hundred thirteen patients had aortic valve replacement (AVR), 73 had mitral valve replacement (MVR), and 62 had multiple valve replacement. Two hundred nine (84%) were in New York Heart Association Class III or IV. The median duration of follow-up was 13 months, and follow-up information was available for 246 (99%) of the patients. The actuarial incidence of freedom from thromboembolism at two years was 98% in the AVR group, 97% in the MVR group, and 87% in the group having multiple valve replacement. There were no documented episodes of valve thrombosis or mechanical failure and no fatal thromboembolic complications. The absence of valve thrombosis is in marked contrast to the results reported with the spherical disc valve. Although longer follow-up is necessary, it appears that the convexoconcave design represents a major improvement in the Björk-Shiley prosthesis.

Adolescent↗
PubMed1984

Penetrating cardiac trauma.

During a 10 1/2 year interval ending in June 1980, 47 patients with penetrating cardiac trauma were managed at The University of Alabama Medical Center. Thirty-nine patients (83%) were male. Mean age was 31 years (range, 13 to 69). Thirty-two patients (68%) sustained stab wounds (SW) and 15 patients (32%) gunshot wounds (GSW). Forty-two patients (89%) arrived hypotensive (systolic blood pressure less than 90 mm Hg). Twenty-seven patients (57%) had evidence of cardiac tamponade (central venous pressure greater than 15 cm H2O) and 25 of these 27 patients were also in shock. Forty patients (85%) presented with a normal sinus rhythm and seven patients (15%) had an idioventricular rhythm or asystole. Overall mortality was 23% (11 of 47 patients). Forty-three per cent of the patients sustaining GSW (6/14) died compared to 17% (5/33) of the patients with SW (p = 0.04). Mortality for the patients in shock was 26% and for those with cardiac tamponade 15%. Mortality was 16% for the patients with both shock and cardiac tamponade. Thirteen per cent of the patients in normal sinus rhythm died, while 87% of the patients with idioventricular rhythm or asystole died (p less than 0.0001). Mortality in penetrating cardiac trauma remains high, particularly in patients with GSW and in those patients presenting with an idioventricular rhythm or asystole.

Adolescent↗
PubMed1983

Surgical treatment of aneurysms of the descending thoracic aorta: an analysis of 85 patients.

We have reviewed our experience with resection of 85 aneurysms of the descending thoracic aorta during a ten-and-one-half year interval ending in June, 1980. There were 39 arteriosclerotic aneurysms, 35 aneurysms associated with chronic aortic dissection, and 11 posttraumatic aneurysms. During repair, a temporary shunt was used in 56 patients (66%), partial (venoarterial) cardiopulmonary bypass (CPB) in 19 patients (22%), and simple aortic cross-clamping in 10 patients (12%). Hospital mortality was 11.8%, and was unrelated to the type of aneurysm or operative method. Spinal cord injury developed in 3 of the 83 patients surviving operation (3.6%), and occurred once with each of the three operative methods. Among the 82 operative survivors without preoperative renal failure, postoperative renal failure requiring hemodialysis occurred in 2 of the 10 patients who had simple aortic cross-clamping (20%), 2 of the 54 who had a shunt (3.7%), and in none of the 18 who underwent partial CPB (p = 0.049). Postoperative renal dysfunction (a rise in the preoperative blood urea nitrogen and creatinine levels of 50% or more) occurred in 27 of the 53 patients (51%) who had preoperative and postoperative determinations. Age, intraoperative hypotension, and the use of simple aortic cross-clamping were significant (p less than 0.05) independent predictors of postoperative renal dysfunction. Intraoperative blood loss and the incidence of reoperation for bleeding did not differ significantly among the three operative methods. We conclude that the aneurysm resection technique and the development of intraoperative hypotension have an important effect on postoperative renal function. Partial CPB may represent the optimal method for preservation of renal function, and may also be the method of choice for elderly patients with preexisting renal dysfunction.

Adult↗
PubMed1983

Factors associated with periprosthetic leakage following primary mitral valve replacement: with special consideration of the suture technique.

Among 435 patients without native valve endocarditis who were followed up to 69 months after primary mitral valve replacement, 25 developed documented periprosthetic leakage. In 10 patients this was associated with prosthetic valve infection. No evidence of prosthetic infection was found in the remaining 15 patients with documented leakages, and they form the basis of the study. Multivariate Cox regression analysis indicated that leakage in the absence of infection was strongly associated with the use of small monofilament suture (2-0 or 3-0 versus 1-0) in a continuous suture technique (92.0% actuarially leak free by 43 months versus 99.0% for continuous 1-0 monofilament sutures or pledgeted mattress sutures; p = 0.01) and with annular calcification (p = 0.01). We did not find (p greater than 0.2) the functional type of mitral valve lesion or its pathology, or the type and size of prosthesis used, to be incremental risk factors.

Coronary Artery Bypass↗
PubMed1983

Combined aortic valve replacement and myocardial revascularization. Experience with a cold cardioplegic technique.

The authors reviewed their experience with combined aortic valve replacement and coronary artery bypass grafting using a standardized cold cardioplegic technique for intraoperative myocardial protection in 54 consecutive patients during a 5-year interval ending in May 1982. Calcific aortic stenosis was the most common indication for aortic valve replacement. Thirty-seven patients (69%) had greater than 50-60% stenoses in at least two of the three major coronary arterial systems. No patient with combined aortic valvular and coronary artery disease had only valve replacement during the study interval, and no patient was refused operation. The mean number of arteries grafted was 2.4. There was one hospital death (1.9%), and one patient (1.9%) had electrocardiographic evidence for perioperative myocardial infarction. One additional patient required postoperative intra-aortic balloon pumping. There have been four late deaths in the followup period extending to 65 months. Survival at 3 years for the entire group was 87%, for the patients with aortic stenosis was 95%, and for the patients with aortic regurgitation or mixed lesions was 65%. There were no cardiac-related deaths among the patients with aortic stenosis and one non-fatal myocardial infarction in the follow-up period. The results with this technique of intraoperative myocardial protection are superior to those reported with previously employed methods (coronary perfusion, hypothermic ischemic arrest) and indicate that coronary artery bypass grafting should be performed in all patients with coexisting aortic valvular and coronary artery disease who require valve replacement. A substantial benefit (increased survival, decreased late myocardial infarction) may exist for the subgroup of patients with aortic stenosis.

Adult↗
PubMed1983

Late results after mitral valve replacement with the Björk-Shiley and porcine prostheses.

The late results of isolated mitral valve replacement were retrospectively evaluated in 357 patients receiving a Björk-Shiley (B-S) tilting disc prosthesis and 96 patients receiving a porcine bioprosthesis (PB) (Vascor or Carpentier-Edwards) between March, 1973, and July, 1978. The groups were comparable with regard to age, sex, New York Heart Association functional class, preoperative cardiac rhythm (sinus or atrial fibrillation), left atrial size (normal or enlarged), and presence of thrombus in the left atrium at operation. All of the B-S and 14 of the PB patients received long-term anticoagulant therapy. The median duration of follow-up was 46 months in the B-S group and 32 months in the PB group. At 5 years, survival was 70% for the B-S and 68% for the PB groups (NS). The percentage of patients free of thromboembolic episodes was 77% for the B-S and 78% for the PB groups (NS). Fifty-six percent of the B-S and 49% of the PB patients were alive and free of thromboembolism, complications related to anticoagulant therapy, or other valve-related complications (dehiscence, degeneration, or endocarditis) (NS). The presence of atrial fibrillation, enlarged left atrium, preoperative thromboembolic episodes, and left atrial thrombus had no effect on the incidence of thromboembolic complications with either prosthesis. From this analysis, it appears that the major advantage of the PB over the B-S prosthesis is its use in patients in whom long-term anticoagulation is contraindicated.

Adult↗