Sigurd Nitter-Hauge

Diabetes Mellitus and Morbidity and Mortality Risks after Coronary Artery Bypass Surgery

Of 1025 patients (912 men, 113 women) who underwent coronary artery bypass grafting and were followed up for a mean of 7.4 years, 45 (4.4%) had diabetes mellitus. Norwegian population is 1.8-2%). Early mortality was not significantly greater among diabetics than in non-diabetics (2.2 vs. 3.1%, odds ratio--OR-0.44, confidence interval--CI- 0.05-3.56). Diabetic patients had no increased risk of perioperative myocardial infarction (OR = 0.87, CI 0.36-2.10) or of low-output syndrome necessitating intraortic balloon pumping (OR = 0.42, CI 0.55-3.05), and no excess incidence of late non-fatal myocardial infarction (relative risk = 0.69, CI 0.10-1.28) or late chronic heart failure (OR = 2.50, CI 0.5-11.0). Long-term mortality was increased in the diabetic patients (relative risk 1.87, CI 1.60-2.14). Thus diabetes did not entail heightened risk of early mortality, perioperative myocardial infarction or low-output syndrome. Nor was there excess risk of recurrent angina pectoris, late non-fatal myocardial infarction or chronic heart failure among the diabetic patients, but the late mortality risk was increased.

Coronary artery bypass surgery in women and in men; early and long-term results. A study of the Norwegian population adjusted by age and sex

OBJECTIVE We wished to analyse early mortality, postoperative low-output syndrome needing intra-aortic balloon pumping support (IABP), total mortality, recurrent angina pectoris and total non-fatal myocardial infarction in women compared with men. Also, the standard mortality ratio (SMR) was estimated to compare the mortality data to the general Norwegian population of comparable sex and age. METHODS A total of 1025 patients; 113 women and 912 men, were submitted to coronary artery bypass surgery at Rikshospitalet, Oslo between August 1982 and December 1986. The patients were followed up until the 1st of January 1993, representing a mean follow-up time of 7.4 years. An exposed/non-exposed cohort study design was used. A power study was carried out. The standardized mortality ratios for women and men were calculated after adjusting for age and sex. RESULTS Crude odds ratio (ORC) of early mortality was 2.0 with a 95% confidence limit (CL95%) of 0.7-5.4. Odds ratio of low output syndrome needing intra-aortic balloon support was 1.7 (CL95% = 0.8-4.2). Statistical significance was not achieved for these end-points. Women did not run an increased hazard of total mortality (ORC = 0.9; CL95% = 0.5-1.5), recurrent angina pectoris (ORC = 1.4; CL95% = 0.8-2.4) or of total non-fatal myocardial infarction (ORC = 0.8; CL95% = 0.4-1.6) when compared with men. Adjusting for confounders did not significantly alter the results. When matched on sex and age and compared to the normal Norwegian population, we found an increased SMR in both men (2.5; CL95% = 2.2-2.9) and women (4.1; CL95% = 2.2-4.9). CONCLUSION The risk of early mortality and low-output syndrome needing intra-aortic balloon support tended to be higher in women compared with men. Women did not run an increased risk of total mortality, recurrent angina or of total non-fatal myocardial infarction. The standard mortality ratio was increased in both men and women, but in particular higher in women, suggesting a more aggressive course of coronary artery disease in operated women than in operated men. However, this difference did not show in the long term follow-up, due to the beneficial effect of coronary artery bypass surgery in both men and women.

Twenty-Five–Year Experience With the Medtronic-Hall Valve Prosthesis in the Aortic Position A Follow-Up Cohort Study of 816 Consecutive Patients

Background— The Medtronic-Hall valve was developed and for the first time implanted in Oslo, Norway, in 1977. A total of 1104 patients received this valve at Rikshospitalet from 1977 to 1987. In the present study, we followed up on all 816 patients undergoing aortic valve replacement over a 25-year period. Methods and Results— This is a retrospective cohort analysis of 816 consecutive patients undergoing aortic valve replacement with the Medtronic-Hall valve at Rikshospitalet, Oslo, Norway, from 1977 to 1987. All patients were contacted by means of questionnaires or telephone. Data were checked against hospital databases and medical records. Date of death was verified by the Norwegian civil registry. Follow-up was 99.6% complete. Survival analysis included operative deaths as well as late deaths. Survival at 25 years was 24.9%. No mechanical failures were found. Valve thrombosis was seen in 4 patients, in 1 case combined with pannus formation. Small valves (20 mm to 21 mm) were associated with reduced survival; however, when controlled for the confounding effects of age and gender, valve size did not remain a significant risk factor. Patient-related factors were important: Older age, female gender, and the need for concomitant coronary artery bypass surgery significantly reduced survival, whereas surgery of the ascending aorta did not. Linearized rates of thromboembolic complications, warfarin-related bleeding, and endocarditis were 1.5%, 0.7%, and 0.16%/patient-year, respectively. At follow-up, 79% of the patients were in New York Heart Association classes I to II. Conclusions— This study confirms the excellent long-term outcome for patients with Medtronic-Hall valves in the aortic position.

Amipaque: A New Contrast Medium in Coronary Angiography: Report of a Double-Blind Study in Man

Isopaque Coronar and Amipaque (metrizamide) were evaluated in a comparative double-blind study of 30 patients with heart disease undergoing selective coronary angiography. Amipaque alone was also used for 9 additional patients undergoing left ventriculography, aortic root injection, and selective coronary angiography. Amipaque resulted in significantly less of a decrease in diastolic pressure and heart rate, reduced chest pain and heat sensation, and longer coronary contrast transit time. Electrorocardiographic parameters and image quality were equivalent with the 2 agents. No pathological changes were noted in the 9 patients undergoing complete angiocardiographic study.

Aortic valve replacement: One-year results with Lillehei-Kaster and Bjork-Shiley disc prosthesis. A comparative clinical study.

Abstract The present study presents clinical and functional results obtained in a randomized series of 68 patients examined one year after single aortic valve replacement with either a Lillehei-Kaster pivoting disc valve or a Bjork-Shiley tilting disc valve. Symptomatic improvement was experienced in 67 per cent of all patients re-examined, and 88 per cent were in functional Classes I and II. In patients with pure aortic valve disease, heart volume was significantly reduced, while a small group of patients with mitral valve disease, in addition, had unchanged or slightly increased heart volume. Regression of left ventricular hypertrophy in the electrocardiogram was also noted in most patients. It is felt that the clinical and functional results may be of the same order of magnitude in patients with the Lillehei-Kaster model as in patients with the Bjork-Shiley prosthesis.

Coronary artery bypass grafting combined with aortic valve replacement in healthy octogenarians does not increase postoperative risk.

Objective: Critical aortic stenosis with or without coronary artery disease is increasingly common in octogenarians. Surgery is the treatment of choice, but indications and results of aortic valve replacement (AVR), particularly when combined with coronary artery bypass grafting (CABG) are debated. We investigated whether the combined procedure of AVR and CABG increased postoperative risk compared with isolated AVR in otherwise healthy octogenarians. Design: In the period 1994-1998, AVR was performed in 94 patients above 80 years, the majority in NYHA class III and IV. Combined AVR and CABG was performed in 52/94 patients. The patients were studied retrospectively by collecting data from hospital records and followed for 0-7 years. Results: Mean age was 82 - 2.3 years, sex (male/female) 33/61, left ventricular ejection fraction 70 - 18%, transvalvular peak pressure gradient 63 - 20 mmHg and aortic valve area 0.5 - 0.2 cm 2 . Early mortality (< 30 days) was 4/42 (9.5%) after AVR and 4/52 (7.6%) after AVR and CABG ( p = NS between groups). Three-year survival was 33/42 (78.5%) after AVR and 42/52 (80.7%) after AVR and CABG ( p = NS between groups). Conclusion: AVR with concomitant CABG in octogenarians with aortic stenosis who are otherwise healthy, may be performed without increased risk.

Seven and one-half years' experience with the Medtronic-Hall valve.

The Medtronic-Hall valve was developed to improve on existing tilting disc valves by reducing the risk of valvular thrombosis. This was to be accomplished by improving the hemodynamics and by allowing the disc to move downstream away from the orifice during opening. The valve was also designed for maximal structural durability to minimize the risk of mechanical breakage. With more than 1,000 Medtronic-Hall valves implanted since 1977, the clinical results have been very encouraging. The rates of thromboembolism and thrombosis are low, there have been no mechanical failures and the hemodynamic function, especially with the smaller valves, is excellent.

Aortic Valve Replacement. A Randomized Study Comparing the Björk–Shiley and Lillehei–Kaster Disc Valves. Late Haemodynamics Related to Clinical Results

In this study, 78 randomized patients with either Björk-Shiley (B-S) or Lillehei-Kaster (L-K) aortic disc valve prostheses were re-admitted for clinical and haemodynamic evaluation. The patients were selected that those with narrow aortic roots were over-represented. Cine-aortography was carried out in 75 patients and left ventricular catheterisation via the transseptal approach was performed in 42. The clinical improvement was striking, although the number of patients still incapacitated was relatively large in patients with the small L-K valves (Nos. 14 & 16). Peak-to-peak and mean systolic pressure differences across the valves were significantly lower in the B-S than in the L-K valves, particularly when the small valve sizes were compared. Left ventricular end-diastolic pressure (LVEDP), which was elevated in most patients before operation, decreased significantly to normal levels in the B-S group. In the L-K group, LVEDP did not decrease significantly and was on the average still above the normal level after operation, probably due to the relatively large pressure gradients. The study indicates that the L-K valves Nos. 14 & 16 in particular represents a resistance to flow that is too large to be acceptable in clinical practice.

Primary clinical experience with the Hall-Kaster valve in the aortic position: results at 3 months including hemodynamic studies.

SUMMARY The Hall-Kaster pivotal disc prosthetic heart valve was introduced in 1977. The primary goal of the design was to obtain the least possible obstruction to flow. Toward this end, innovations in the tilting axis, disc guidance mechanisms, and disc translational freedom combine to improve flow through both orifice segments of the open valve. The present study reports the primary clinical and hemodynamic findings in 28 patients (mean age, 53.8 years) with aortic valve disease, examined 3 months after insertion of the Hall-Kaster pivotal disc valve. The hemodynamics findings displayed low gradients and high calculated orifice areas. Satisfactory flow was observed through both the major and minor openings of the prosthesis. There were no arterial thromboembolic episodes. The increase in serum lactate dehydrogenase activity was moderate, indicating a slight-to-moderate intravascular haemolysis.

Renal function studies in hyponatremic cardiac patients with edema (dilution syndrome)

Abstract In the present series, cardiac output, renal blood flow corrected for PAH extraction rate, and glomerular filtration rate were measured in 8 patients with decompensated congestive heart failure with hyponatremia and normal or increased exchangeable sodium (dilution syndrome). The renal sodium reabsorption and oxygen consumption have also been measured. The cardiac output was reduced to less than half the normal. The renal blood flow was reduced to a greater degree than cardiac output, indicating a specific diversion of blood away from the kidneys. The glomerular filtration rate was also reduced, but to a lesser extent than the renal plasma flow, giving filtration fractions higher than usually reported. The reduction in renal blood flow and in glomerular filtration rate or the increase in filtration fraction had no relation to the magnitude of exchangeable sodium. In our patients, variations in the glomerular filtration rate revealed constancy in the sodium reabsorptive mechanism. The renal oxygen consumption was found to vary independently of the sodium reabsorption. The findings were compatible with an increased passive back diffusion of sodium in the tubular lumen in patients with advanced congestive heart failure. Data from the present study support the assumption that such passive re-entry for sodium is related to an increased filtration fraction, although other mechanisms must also be considered.