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Biomedical subjects

H Laks

Publications and source records attributed to H Laks.

At least 289 records · Page 16Linked to original sources
PubMed1979

The importance of myocardial protection in combined aortic valve replacement and myocardial revascularization.

To determine the importance of different methods of myocardial protection for combined aortic valve replacement and coronary revascularization, we analyzed the records of 82 consecutive patients who underwent the combined procedure between 1973 and 1978. Sixty-three (77%) had angina and 63 (77%) were in New York Heart Association Functional Class III or IV. Moderate to severe left ventricular impairment was present in 59%, and the mean number of diseased vessels was 1.9 per patient. Group I consisted of 18 patients with intermittent ischemia, almost all of whom had operation between 1973 and 1976. Group IIa consisted of 24 patients operated on between 1973 and December, 1976, with coronary perfusion, and Group IIb had 18 patients in whom a similar technique was used in 1977 and 1978. Group III consisted of 22 patients operated on in 1977 and 1978 in whom cold chemical cardioplegia was used. The early mortality (less than 30 days) for Group I was 50% and for Group IIa 29%. There were no deaths in Group IIb and Group III. The incidence of perioperative myocardial infarction was 21% in Group I, 6% in Group IIa, 11% in Group IIb, and zero in Group III. The incidence of cardiogenic shock requiring prolonged inotropic support and intraaortic balloon counterpulsation was significantly less in Group III (9%) than in Group IIb (50%) (p less than 0.05). If other manifestations of myocardial injury, such as perioperative infarction and cardiogenic shock requiring intraaortic balloon counterpulsation or inotropic support, are taken into consideration, cold chemical cardioplegia appears to provide better myocardial protection than coronary perfusion of the fibrillating heart.

Adult↗
PubMed1979

Cold blood as the vehicle for potassium cardioplegia.

Cold blood with potassium, 34 mEq/L, was compared with cold blood and with a cardioplegic solution. Three groups of 6 dogs had 2 hours of aortic cross-clamp while on total bypass at 28 degrees C with the left ventricle vented. An initial 5-minute coronary perfusion was followed by 2 minutes of perfusion every 15 minutes for the cardioplegic solution (8 degrees C) and every 30 minutes for 3 minutes with cold blood or cold blood with potassium (8 degrees C). Hearts receiving cold blood or cold blood with potassium had topical cardiac hypothermia with crushed ice. Peak systolic pressure, rate of rise of left ventricular pressure, maximum velocity of the contractile element, pressure volume curves, coronary flow, coronary flow distribution, and myocardial uptake of oxygen, lactate, and pyruvate were measured prior to ischemia and 30 minutes after restoration of coronary flow. Myocardial creatine phosphate (CP), adenosine triphosphate (ATP), and adenosine diphosphate (ADP) were determined at the end of ischemia and after recovery. Changes in coronary flow, coronary flow distribution, and myocardial uptake of oxygen and pyruvate were not significant. Peak systolic pressure and lactate uptake declined significantly for hearts perfused with cold blood but not those with cold blood with potassium. ATP and ADP were lowest in hearts perfused with cardioplegic solution, and CP and ATP did not return to control in any group. Heart water increased with the use of cold blood and cardioplegic solution. Myocardial protection with cold blood with potassium and topical hypothermia has some advantages over cold blood and cardioplegic solution.

Adenosine Diphosphate↗
PubMed1979

Subclavian arterioplasty for the ipsilateral subclavian-to-pulmonary artery shunt.

A new technique is described to avoid kinking and improve flow in the ipsilateral subclavian-to-pulmonary artery shunt. Experience with this procedure is reviewed in 35 infants and children with a variety of cyanotic congenital heart disease, including 10 with tricuspid atresia. Of these, 17 had had previous shunts: a Waterston shunt in six, a Glenn shunt in six, and a contralateral Blalock-Taussig shunt in five. The mean age was 5.6 years (range, 1 day to 16 years), and the mean follow-up was 24 months (range, 11 months to 4.5 years). There were no early deaths (less than 30 days), but there were two late deaths. There were three shunt failures at 2 weeks, 1 month, and 10 months; two of the failures were in infants aged 1 day and 4 days at operation. There were no late shunt failures. The patency by the life table method was 91.4% at 6 months, 88.5% at 1 year, with no further drop-off. It is concluded that subclavian arterioplasty can be performed safely and offers improved shunt patency in comparing to the ipsilateral Blalock-Taussig shunt.

Adolescent↗
PubMed1979

Cold blood cardioplegia.

The technique of myocardial protection by means of a cardioplegic solution consisting of cold blood (10 degrees C) with potassium (30 mEq. per liter) is described. A disposable cooling coil is used and a separate pump head for coronary perfusion is avoided. The aortic perfusion cannula can be used for venting of the left ventricle and subsequently for venting of air. This method was used in 125 consecutive patients undergoing coronary revascularization and in 73 consecutive pediatric cardiac surgical procedures with excellent results.

Blood↗
PubMed1979

Late failure of porcine valve heterografts in children.

Heterograft porcine valves have gained wide acceptance in replacement of diseased cardiac valves, and their clinical performance in adults has been very satisfactory over follow-up periods of up to 8 years. Valve replacement in children is relatively infrequent and experience with porcine xenografts is necessarily small. Our combined experience at three university hospitals has been with 25 children, 17 months to 16 years of age, who have been followed for 10 to 54 months (mean follow-up 33 months). Porcine valves were used to replace the aortic valve in nine, the mitral valve in seven, both valves in two, the tricuspid valve in two, and the pulmonary valve in five patients. Severe bioprosthetic valve dysfunction has occurred in five (20%) of these patients so far and necessitated replacement because of severe stenosis in mitral (two) or aortic (three) valve prostheses at 18 to 45 months after implantation; one postoperative death occurred among the five reoperations. Pathological examination showed extensive fragmentation of collagen with focal heavy calcification and degeneration. In addition we have encountered deterioration and calcification of two porcine valves in 23 valved conduits followed for 12 to 70 months (mean 43 months), requiring removal and replacement of the valves 65 and 67 months after implantation. This experience indicates a disquietingly high incidence of relatively early failure of porcine xenograft valves in children. This is significantly higher than the failure rate observed in adult patients. The failure rate is not consistently related to the small size of an implanted valve which becomes relatively narrow with the growth of the patient, leading to excessive turbulence and trauma to the prosthesis. Other factors, including increased turnover of calcium and accelerated rejection in growing children, may contribute to these failures and should be examined in order to improve long-term results. A satisfactory performance would make heterografts the ideal valvular prosthesis in children, since anticoagulation is avoided.

Adolescent↗
PubMed1978

Coronary revascularization under age 40 years. Risk factors and results of surgery.

Groups of patients such as the elderly, the diabetic and women have been studied to evaluate the effectiveness of coronary revascularization. In this report 77 patients under age 40 years undergoing coronary revascularization were studied. There was a high prevalence rate of predisposing factors. Sixty-eight percent reported a family history of heart disease and 27 percent a history of diabetes; 57 percent were hypertensive, 43 percent were overweight, 91 percent smoked, 5 percent were diabetic and 16 percent had abnormal glucose tolerance curves. Sixty-four percent had hypercholesterolemia (cholesterol 250 mg/100 ml) and 56 percent hyperlipidemia. Forty-four percent had had a previous myocardial infarction; 95 percent had angina pectoris, 12 percent preinfarction angina and 9 percent congestive cardiac failure. There were no operative deaths. The incidence rate of perioperative myocardial infarction (new Q waves in the electrocardiogram) was 4 percent. The mean length of of follow-up was 26 months (range 6 months to 5 years). The late mortality rate was 4 percent. Eight percent had a late myocardial infarction. Overall graft patency was 85 percent. Sixty-seven percent of patients were free of angina, and 17 percent were in improved condition. Seventy-one percent returned to work, while 29 percent remained unemployed. This study shows that in young patients, coronary revascularization is associated with low mortality and morbidity rates and that, despite the wide prevalence of predisposing factors, the prognosis and graft patency rate of these patients are similar to those of other groups.

Adult↗
PubMed1978

Repair of aortic coarctation in the first year of life.

Twenty-five infants under 1 year of age (mean, 10.3 weeks and 4.0 kg) underwent coarctation repair. Eight had ventricular septal defect (VSD), 3 had transposition of the great arteries with VSD, and 5 had severe tubular hypoplasia. One infant required mitral valve replacement, and 1 required repair of total anomalous pulmonary venous return. Fifteen had repair by primary anastomosis. Seven underwent Dacron or subclavian aortoplasty; the advantages and technique of angioplasty are reviewed. Three patients required bypass grafts. Seventeen patients survived operation. All 5 patients who had severe tubular hypoplasia died postoperatively. The mortality for repair of coarctation with VSD by simultaneous pulmonary artery banding was high; for coarctation with VSD we currently recommend repair without banding, followed by VSD closure if indicated. Three infants have been treated successfully in this manner, with early VSD closure in 1 and regression of the VSD during follow-up in 2. The 17 survivors have been followed for a mean of 41 months with 3 late deaths. Of the 17 survivors, all of whom had a primary anastomosis, 3 have residual gradients. Of the 11 survivors who had preoperative hypertension, 6 are still hypertensive; 3 of these have a gradient between the upper and lower extremities. It is striking that 3 have persistent hypertension despite repair under the age of 1 year.

Aortic Coarctation↗
PubMed1978

The Blalock-Taussig shunt in the neonate.

With improvements in the techniques of microvascular surgery, the Blalock-Taussig shunt has been applied to smaller infants. We report our experience in 17 neonates (mean age 9 days, mean weight 3.2 kg) who underwent emergency shung operations. The early mortality was 17.6% (3 of 17), with only 1 death (7%) from renal failure and sepsis, in the last 14 patients. Three shunts were patent but inadequate and required a secondary procedure, which was successful in all 3. There were 3 patients with late shunt failures at a mean of 15 months postoperatively, while 2 are still doing well at 15 and 18 months. No patients developed congestive cardiac failure. The late mortality was high (5 of 14), but was due to late shunt failure and was preventable in only 1 patient. These results are encouraging, and we continue to perform the Blalock-Taussig shung in neonates. It is hoped that improvements in technique will reduce the incidence of inadequate shunts.

Adolescent↗
PubMed1978

A simple method of cold coronary perfusion.

Hypothermic coronary perfusion lengthens the safe duration of anoxic arrest. Intermittent selective hypothermic coronary perfusion provides extended myocardial protection. We describe a method of achieving profound myocardial hypothermia by selective deep hypothermic coronary perfusion using a cooling coil without a separate pump head.

Adult↗
PubMed1978

Myocardial revascularization in women.

During the period January, 1970, through June, 1977, 1,541 patients underwent coronary artery bypass grafting; 241 of them were women (15.6%). Operative mortality rates for the entire study were 2.4% in men and 3.7% in women, but they showed a marked decline in women during 1975 to mid-1977, with only 2 deaths in 140 patients (1.4%). Women comprised a larger percentage of patients (16.7%) in these later years. Women were slightly older, received fewer grafts, had better preservation of ventricular function on preoperative studies, and had more severe anginal symptoms than men. Patency rates were significantly lower in women at 1 month, 1 year, and 3 years. Five-year survival was not significantly different between women (88.3%) and men (93.5%). Many of these findings may be explained on the basis of women having smaller coronary arteries than men. These favorable results differ from earlier reports of higher mortality rates in women and indicate that myocardial revascularization should not be withheld from female patients.

Age Factors↗
PubMed1978

Severe cyanosis due to atrial septal defect and an anomalous inferior vena caval valve.

Uncomplicated atrial septal defect is often associated with mild arterial desaturation. A case is reported with severe cyanosis and life-threatening hypoxemia due to an atrial septal defect. Cardiac catheterization revealed normal right heart pressures and an atrial septal defect with shunting of inferior vena caval blood into the left atrium. At surgery an anomalous inferior vena caval valve was found directing inferior vena caval blood into the left atrium. The embryologic basis for this association is discussed. The delayed onset of severe cyanosis may have been contributed to by the thoracic scoliosis.

Cyanosis↗
PubMed1978

Myocardial protection by intermittent perfusion with cardioplegic solution versus intermittent coronary perfusion with cold blood.

The myocardial protection provided by cardioplegic solution using buffered, isosmotic potassium (30 mEq. per liter) was compared with intermittent cold coronary perfusion for 2 hours of aortic cross-clamping in dogs. The cardioplegic solution (Group CS) or cold blood (Group CB) was infused every 15 minutes through a cooling coil to reduce the perfusate temperature to 5 degrees C. Myocardial function after 30 minutes of reperfusion and rewarming was reduced in Group CB with a significant reduction in peak systolic pressure at a left ventricular (LV) balloon volume of 20 ml. and a significant reduction of dp/dt. In contrast, in Group CS, LV function was unchanged from the base-line period. LV compliance also was significantly reduced in Group CB while being unchanged in Group CS. Myocardial extravascular water content, obtained by dessication, was significantly higher in Group CB than in Group CS, which may explain the reduction in compliance. Electron microscopy showed normal ultrastructure in Group CS but extracellular edema in Group CB. Total coronary blood flow showed a sustained increase during reperfusion in both groups. Oxygen consumption rose with rewarming to base-line levels in both groups, whereas lactate and pyruvate consumption was reduced in both groups, particularly Group CB. Cardioplegic solution thus appears to be superior to the intermittent perfusion of cold blood for myocardial protection. The addition of potassium arrest, by markedly reducing myocardial metabolism, improves the protection afforded by cold blood perfusion alone.

Animals↗
PubMed1977

Nonsyphilitic coronary ostial stenosis.

From October 1970 to June 1977, a total of 15 patients (12 women) were seen with atherosclerotic coronary ostial stenosis (14 left, one right). All patients had angina and two had aortic valve disease. Additional coronary arterial disease was present in nine. One patient declined surgery and died four months later after myocardial infarction. All patients had coronary bypass grafts and two had aortic valve replacement. One patient with valve replacement and one with preoperative cardiogenic shock died postoperatively. Angina recurred nine months postoperatively in one patient; the others (11) are free of angina. Postoperative catheterization from two weeks to 4.5 years in ten of 12 showed 11 of 13 vein grafts and eight of nine internal mammary artery grafts to be patent. In three patients, only a single left-sided coronary bypass was placed to the left anterior descending artery, because the circumflex branches were too small. Ideally, two left-sided bypass grafts should be placed for left ostial disease.

Adult↗
PubMed1977

Internal mammary artery cannulation.

A technique of internal mammary artery cannulation is described. This approach offers a safe method for arterial monitoring in infants undergoing thoracotomy for palliative cardiac procedures.

Catheterization↗