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The Doppler echocardiographic characteristics of 70 prosthetic valves in 35 patients are reported. Twenty nine patients had a Björk-Shiley prosthesis in both mitral and tricuspid positions and six had Carpentier-Edwards valves in both sites. Five of the patients had abnormal tricuspid prostheses on the basis of clinical and echocardiographic criteria. Pulsed wave Doppler echocardiography was used in all examinations. The pressure half times for the normal tricuspid prosthetic valves, 105 (40) ms (Björk-Shiley) and 97 (53) ms (Carpentier-Edwards), were significantly longer than those of normal mitral prosthetic valves, 75 (18) ms (Björk-Shiley) and 83 (15) ms (Carpentier-Edwards). The range of pressure half times for the abnormal tricuspid valves (237-530 ms) was distinct from that of the apparently normal tricuspid prosthetic valves (38-197 ms). There was an increase in the peak velocity of the obstructed tricuspid prosthetic valves (1.69 (0.12) m/s) in comparison with normal prostheses (1.06 (0.26) m/s). The normal range of pressure half times for the Björk-Shiley and Carpentier-Edwards valves in the mitral position is not applicable to the same valves in the tricuspid position. The valve appears to function well with very long pressure half times but a pressure half time of greater than 200 ms coupled with a peak velocity of greater than 1.60 ms without significant valve regurgitation indicates tricuspid obstruction of the tricuspid prosthetic valve.

Thrombotic obstruction is the most feared complication of the Björk-Shiley tilting disc prosthesis. From 1971 to 1982 1186 Björk-Shiley valves were implanted in 900 patients. There were 93 deaths in hospital. Eight hundred and seven patients have been followed for a total of 4146 patient years; 14 patients were lost to follow up. Nineteen cases of thrombotic obstruction were identified at necropsy or at a repeat operation in the study group. The mitral prosthesis was thrombosed in 16 patients, the aortic in two, and the tricuspid in one. The incidence for this complication has been calculated to be 0.46 per 100 patient years for all valve positions, 0.79 for single mitral valve replacements, 0.18 for aortic replacements, and 0.63/100 for the tricuspid position. The maximum possible incidence of this complication in this population has been calculated to be 1.4 per 100 patient years. The mortality rate was 41.7% for reoperation and 63% for the development of the complication. Risk factors that have been identified are inadequate anticoagulant control, poor preoperative exercise capacity, and possibly also the implantation of small prostheses.

The possible relationship between angiotensin II -- the end product of the renin-angiotensin system, and the increase in peripheral vasoconstriction associated with cardiopulmonary bypass, has been investigated in 12 patients undergoing elective open-heart surgical procedures. Plasma angiotensin II (AII) levels were measured by radio-immunoassay at the start and the end of the period of cardiopulmonary bypass. Measurements of peripheral vascular resistance index were made at the times of AII sampling. Plasma AII levels rose during CPB from 78.0 to 231.3 pg.cm-3 (normal values less than 35 pg.cm-3). Peripheral vascular resistance index also rose during perfusion from 20.87 to 27.83 units. The rise in plasma AII levels and in peripheral vascular resistance index were correlated for each of the 12 patients. A highly significant correlation was obtained (r = 0.91; P less than 0.001). These results confirm the presence of parallel rises in plasma angiotensin II levels and in peripheral vasoconstriction during conventional non-pulsatile cardiopulmonary bypass, and suggest that increased plasma AII levels may be principal causative factor in the increased vasoconstriction associated with open-heart surgical procedures.

Over a period of five years (1983-88) 210 Björk-Shiley monostrut mechanical tilting disc prostheses were implanted in 176 patients over the age of 60. There were 61 aortic valve replacements, 86 mitral valve replacements and 29 multiple replacements. Patients were aged between 61 and 78 years (mean 65.5 years), 89% were in NYHA grades III and IV preoperatively and 34.6% had had previous cardiac surgery. Concomitant coronary surgery was performed in 15.9%. Early mortality was 9.1%. Follow-up is 100% complete. There were eight late deaths (3.1 per 100 patient years) of which three were valve-related (prosthetic endocarditis 2, periprosthetic leak 1). Actuarial survival at five years is 98% for aortic valve replacement and 93% for mitral valve replacement. There were no major embolic events and four possible minor embolic events. Overall freedom from anticoagulant complications was 88.9% at five years. No deaths occurred because of anticoagulant-related haemorrhage. There were no episodes of valve failure (thrombotic obstruction or mechanical disruption). Six patients were reoperated for complications: two for periprosthetic leak and three for prosthetic endocarditis. These results compare favourably with those of other valve substitutes and justify the continuing use of the Björk-Shiley monostrut tilting disc prosthesis in the elderly.

The development of abnormally high plasma sodium and plasma osmolality levels is described in 5 patients following open-heart surgery involving prosthetic replacement of the tricuspid valve. These biochemical abnormalities developed in the early post-operative period and were associated with an excessive diuresis during the first 3 to 4 days after operation. Biochemical correction required a prolonged, high volume intravenous water load, and was paralleled by progressive clinical improvement, notably in peripheral circulation, tissue turgor and cerebral function. Plasma sodium and osmolality levels and observed fluid balance in 20 patients undergoing similar surgical procedures for tricuspid valve lesions fail to show this hypernatraemic, hyperosmolar state, and indicate that the majority of such patients have a markedly positive observed fluid balance in the early post-operative period. These differences are statistically highly significant (p less than 0.001). Consideration of urine/plasma osmolality levels reveals a transient but highly significant impairment of renal concentration in the hypernatraemic patients (p less than 0.001).

The response patterns of plasma cortisol and plasma free cortisol have been studied in 20 consecutive patients undergoing cardiac surgery involving the use of heart-lung bypass. Sixteen consecutive patients undergoing closed mitral valvotomy have been used as controls. Total plasma cortisol levels fell at the onset of extracorporeal circulation (ECC) and did not rise significantly throughout the period of ECC. The peak cortisol level in the bypass patients occurred at 24 hours postoperatively with elevated levels still present at 48 hours. This pattern was significantly different from the control patients (P less than 0.001) who exhibited the typical cortisol stress response pattern. Synthetic ACTH stimulation of the adrenal cortex during heart-lung bypass produced a positive response (i.e., a rise in plasma cortisol greater than 7.5 mug/100 ml) in all six patients studied while the six mitral valvotomy patients had no response to synthetic ACTH administration during operation (P less than 0.01). Plasma free cortisol estimations indicate that a rapid and significant rise in % free cortisol occurred at the onset of ECC, but that despite the rise in percentage free, the overall plasma free cortisol concentration (i.e., total plasma cortisol X % free) was significantly lower during ECC in the bypass patients when compared with control (P less than 0.01). Twenty-four hours postoperatively these concentrations were significantly higher in the bypass patients (P less than 0.001).

Between 1970 and 1984, 1,574 Björk-Shiley valve prostheses have been implanted in 1,171 patients in Glasgow. Between 1970 and 1980, 1,023 standard disc prostheses were implanted in 729 patients: 184 had aortic valve replacement, 323 mitral, and 222 multiple valve replacement. Between 1980 and 1984, 551 convexo-concave valves were implanted in 442 patients: 125 had aortic, 228 mitral, and 89 multiple valve replacement. Concomitant coronary artery bypass grafting was performed in 9.2% of the latter group as compared with 2.7% of the earlier group. The overall hospital (30 day) mortality for the group with the standard disc prosthesis was 10.4% and for patients with the convexo-concave prosthesis, 7.0%. Cumulative follow-up extends to 4,125 patient-years--standard disc group 3,378 patients-years, range 4 to 14 years (mean 5.2 years); convexo-concave group 747 patient-years, range 1.5 to 5.3 years (mean 1.9 years). The late mortality is 3.8% per patient-year--standard disc group 2.9% per patient-year and convexo-concave group 4.3% per patient year (no significant difference). Actuarial survival rate at 12 years for the whole group, excluding operative deaths, is 69.4% +/- 6.3%. The freedom from all valve-related complications at 12 years is 65.9% +/- 6.5%. there is no significant difference in the incidence of most major complications between the standard disc and convexo-concave prostheses apart from the occurrence of mitral valve thrombosis (p less than 0.05) in the standard disc group and outlet strut fracture (p less than 0.005) in the convexo-concave group. These results confirm the excellent long-term performance of the Björk-Shiley tilting disc prosthesis.

Pulsatile perfusion has been shown to offer significant haemodynamic advantages over non-pulsatile perfusion in many experimental studies. Clinical acceptance of pulsatile perfusion during cardiac surgical procedures has, however, been hampered by the lack of technologically satisfactory pulsatile pump systems, and by inadequate clinical experience of routine use of pulsatile perfusion. The recent introduction of reliable pulsatile pump systems with low haemolysis characteristics has made possible the clinical validation of the previous experimental studies. We describe the results of a prospective study of mortality, haemodynamic morbidity, and haematological status, in 350 consecutive adult patients submitted to cardiopulmonary bypass procedures in a surgical unit over a 12-month period. One hundred and seventy five patients were perfused with conventional non-pulsatile flow and 175 with pulsatile flow, using a modified roller-pump pulsatile system (Cobe-Stockert). The groups were closely similar in terms of preoperative characteristics, referral category, and pathology requiring surgery. Operative techniques, bypass parameters, and anaesthetic regime were standardised in both groups. The results were as follows. (1) Total mortality was significantly lower in the pulsatile group (4.6%) compared with the non-pulsatile group (10.3%), p = 0.06. (2) The incidence of deaths attributable to post-perfusion low cardiac output was significantly lower in the pulsatile group (1.1% compared with 6.3%, p = 0.02). (3) Requirement for mechanical (intra-aortic balloon) or drug circulatory support was significantly lower in the pulsatile group. (4) The use of pulsatile perfusion was not associated with any increase in haemolysis, blood cell depletion, or postoperative bleeding problems.

Perioperative digoxin concentrations were measured in 20 unselected adult patients undergoing coronary surgery. None of the patients were receiving treatment with digoxin. A digoxin-like immunoreactive substance was found in 16 patients postoperatively. This substance, if pharmacologically active, may have important clinical implications in the management of patients after open heart surgery.

Previous studies have indicated that, during nonpulsatile cardiopulmonary bypass, the anterior pituitary gland fails to respond to the tropic stimulus of thyrotropin-releasing hormone (TRH). This is in contrast to the normal response seen during closed cardiac and general surgical procedures. The Stöckert pulsatile pump system described in Part I has been employed in a comparative study of TRH responses in 20 patients subjected to pulsatile or nonpulsatile perfusion during open-heart surgery. In the nonpulsatile group, a consistently subnormal response to TRH injection was again found. In the pulsatile group, however, the pituitary response to TRH was normal in nine patients out of 10. The quantitative difference between the groups was statistically highly significant (p less than 0.005). These results indicate that the subnormal pituitary function seen with nonpulsatile bypass may be prevented by the use of pulsatile perfusion.

Massive blood transfusion and extracorporeal circulation result in bombardment of the small pulmonary arterioles with micro-aggregates which are mainly composed of cellular degradation products, damaged platelets and leukocytes, fibrin strands, portions of cellular membrane and protein precipitates. Such amorphous material can cause patients to die of respiratory insufficiency without underlying chest trauma. Increasing amounts of stored blood are transfused to patients and extracorporeal circulation has become one of the most useful techniques for surgeons. Unfortunately, these procedures are often accompanied by disturbing post-operative consequences. This is because micro-aggregates invade the capillary network of several organs, especially lungs, kidneys, brain and retina. It is why blood filtration has recently gained added interest because of widespread efforts to minimise the number or emboli which are either transfused or reinfused to the patient through the blood return line.

With the application of new power sources to pacemakers, considerable improvement has been achieved in the theoretical implant lifetime of current pulse generators, and equally reliable electrode leads will be necessary to ensure long-term pacing. The durability of the electrodes implanted in the past ten years in this centre has been carefully studied. The findings suggest that the use of a more durable conductor material and development of the concept of a 'fail safe' lead (using multi-filament conductors or a secondary conductive pathway along the electrode) will be necessary to match with the implant lifetime of the newer pulse generators. The diagnosis and management of broken conductors is discussed.

The operation on and subsequent course of 88 patients with valve replacements using Björk-Shiley tilting disc prostheses has been reviewed in terms of mortality, clinical results, and valve function. The follow-up period varied between 6 months and 2 years. The hospital mortality was 17% and late mortality 8%. Of those who left hospital, 75% returned to full normal activity and required less (or no) drug therapy other than maintenance anticoagulation. There was one transient embolic episode. Significant intravascular haemolysis does not occur with this prosthesis.

A system of definitions for valve-related complications is proposed for use in the assessment of the clinical performance of prosthetic heart valves.

Organic disease of the tricuspid valve required surgery in 18% of all patients undergoing valve replacement over a five-year period. Differentiation of organic from functional disease is difficult and may be made only at open-heart surgery. The results of a series of 56 patients who underwent tricuspid valve replacement are presented; of these, 53 had organic disease. Operative mortality at the end of five years had fallen to 7% with significant clinical improvement in 79% of patients, a reduction in cardiothoracic ratio in 81%, and a low incidence of postoperative tricuspid incompetence.

A system is described which will accept, store, retrieve and analyze information on large numbers of patients who undergo valve replacement surgery. The purpose of the database is to yield readily available facts concerning the patient's clinical course, prosthetic valve function, length of survival, and incidence of complications. The system uses the Apple Macintosh computer, which is one of the current examples of small, desk-top microprocessors. The software for the input, editing and analysis programs has been written by a professional software writer in close collaboration with a cardiac surgeon. Its content is based on 8 years' experience of computer-based valve follow-up. The system is inexpensive and has proved easy to use in practice.

The results of cardiac surgery in 7 patients with functioning renal transplants are reported. In all cases surgery was carried out using standard operative techniques whilst renal perfusion was enhanced where necessary by the use of a dopamine infusion. The immediate postoperative course was uneventful in all cases, though 2 out of 4 patients with ischemic heart disease have since experienced recurrent symptoms. Cardiac surgery may be performed in patients with functioning renal transplants with acceptable mortality and morbidity.

During 1986, 343 consecutive patients who underwent isolated coronary bypass grafting were given 10 mg of propranolol three times daily for six postoperative weeks to help prevent supraventricular tachyarrhythmias. The incidence of these arrhythmias in this group was compared to that in a similar group of 337 consecutive patients who underwent coronary surgery in 1984 at the same institution and did not receive propranolol. There was no significant difference in the overall incidence of such arrhythmias between the propranolol group (10.8%) and the control group (10.4%). In preoperatively beta-blocked patients, the arrhythmia incidence in the propranolol group (9.9%) was lower than that in the control group (13.8%) but the difference did not achieve statistical significance. The two groups were also similar with respect to the ventricular response rates at the onset of the arrhythmia and the effectiveness of therapeutic intervention. These results suggest that propranolol in the above dosage does not significantly reduce the incidence of supraventricular tachyarrhythmias after myocardial revascularisation.

Life-threatening peri-prosthetic incompetence developed with two successive nickel-containing mitral-valve prostheses in a patient allergic to nickel. Neither prosthesis had been incorporated satisfactorily. Her present nickel-free prosthesis seems to be satisfactory 22 months after insertion. Since allergy to nickel may have been involved in the failure of these prostheses, it is recommended that nickel-sensitive patients should be given nickel-free prostheses.

Marked alterations in levels of circulating thyroid hormone were found in patients undergoing cardiopulmonary bypass with a rise in the free thyroxine and a fall in the free triiodothyronine levels. Studies using thyrotropin-releasing hormone during bypass demonstrated a blunted response to this stimulus. This reduced response is related to changes in thyroid hormone levels and it is suggested that bypass surgery may have a direct inhibitory action on thyroid-stimulating hormone release at the hypothalamo-pituitary level. The potential significance of these hormonal changes is discussed.

An unusual case of chylothorax is described in a 4-year-old child after repair of a ventricular septal defect and ligation of a patent ductus arteriosus through a median sternotomy. Left chylothorax developed after a latent period of six days and was treated initially with continuous drainage and parenteral supplementation of proteins and lipids. Operative intervention with oversewing of the site of the leak in the anterior mediastinum proved necessary after three weeks. The anatomical variations of the thoracic duct are outlined to explain the occurrence of chylothorax after diverse intrathoracic operations. The physiological effects of a thoracic duct fistula and various aspects of management are reviewed.

Thirty patients with severe preoperative pulmonary hypertension (pulmonary artery pressure range 90-165 mmHg, mean 118 mmHg) were reviewed following single mitral valve replacement, with prosthetic valves, within the last 10 years (1964-74). The early and late mortality for this group was no different from that of the total series of mitral valve replacements performed over the same period. Marked postoperative clinical improvement was accompanied by corresponding radiological and electrocardiographic changes. In addition there was a statistically highly significant haemodynamic improvement in the 21 survivors (mean survival time 5 1/2 years). At recatheterization the mean pulmonary artery pressure was 41-5%, the mean wedge pressure 46-3%, and the transpulmonary gradient (PAm-LAm) 36-1% of the preoperative values. It is concluded that gross pulmonary hypertension is not per se a contraindication to mitral valve replacement surgery.

The systemic haemodynamic changes occurring in the immediate post-operative period were examined in a series of patients undergoing closure of atrial septal defect (A.S.D.) and in a consecutive series of all patients undergoing open-heart surgery in this Unit. Significant systemic hypertension was observed in 47.5% of patients in the A.S.D. series. In an attempt to explain this finding, several other haemodynamic variables were examined in relation to the systemic blood pressure. There was no correlation between central venous pressure or blood loss and systemic blood pressure. However, there was an inverse correlation between blood balance and systolic and diastolic blood pressure at 4 hours after operation. The explantation of this finding is unclear but it may be due to the effects on atrial receptors of lower right atrial and pulmonary artery pressures following closure of the A.S.D. Although the post-operative systemic hypertension was transient in most cases, it may produce adverse effects in the early post-operative period and therefore treatment with hypotensive agents should be considered in severe cases.

A new, commercially available roller pump system able to deliver pulsatile and nonpulsatile flow has been studied in patients undergoing elective open-heart surgical procedures. The pulsatile pump (Stöckert Instrumente) may be used with standard extracorporeal circuit equipment and consistently produces a peripheral arterial pulse pressure of 25 to 30 mm. Hg at mean flow rates of 3.5 to 4.0 L. per minute. Twenty patients, arbitrarily allocated to pulsatile or nonpulsatile groups, have been studied. There were no significant differences between the groups in respect of age, weight, bypass time, pump flow, or mean arterial pressure during bypass. Comparative studies of the hematologic effects of pulsatile and nonpulsatile perfusion were carried out. There was no evidence of increased hemolysis with pulsatile flow, nor was there increased depletion of red blood cells (RBC's) or platelets in the pulsatile group. This pulsatile pump system may therefore be used to produce pulsatile perfusion during cardiopulmonary bypass without the fear of producing excessive blood cell trauma.

The effect of hemodilution on plasma levels of total cortisol and free cortisol was studied in 12 patients undergoing open-heart surgery. In each case, at the onset of extracorporeal circulation (ECC) the hematocrit value was rapidly reduced to 25 to 30 per cent and was maintained around this level during perfusion. Total plasma cortisol levels fell significantly with the hemodilution (p less than 0.0001), but the plasma concentration of free, biologically active cortisol was maintained at its pre-dilution level because of an increase in the percentage of plasma cortisol existing in the free form. There was a highly significant correlation between the degree of hemodilution and the percentage rise in the free cortisol fraction (r = 0.79; p less than 0.001). These results indicate the presence of a compensatory mechanism associated with cortisol binding which maintains the plasma level of free, biologically active cortisol when hemodilution has reduced the plasma level of total cortisol.

Mechanical cell damage was studied in vitro with three types of prostheses: Starr-Edwards, Kay-Shiley and Björk-Shiley valves. Mechanical cell damage was found to be closely related to the flow characteristics in the prosthesis. Considering valves of similar orifice diameter, Björk-Shiley valves produced the lowest rate of haemolysis. This is due to the improved haemodynamic characteristics of the valve which resulted from the laminar type of flow. With Starr-Edwards valves, smaller sizes produced unacceptably high rates of haemolysis. Increasing the mean forward flow across the valve resulted in a disproportionate rise in the energy loss and the rate of haemolysis when compared with Björk-Shiley valves of similar annulus diameters.

Previous studies have indicated that a significant reduction in plasma cortisol levels occurs during nonpulsatile cardiopulmonary bypass as a result of adrenocorticol hypofunction. The Stöckert pulsatile pump system described in Part I has been employed in a comparative study of plasma cortisol levels in 20 patients subjected to pulsatile or nonpulsatile perfusion during open-heart surgery. The plasma cortisol response pattern in the nonpulsatile group was identical to the pattern previously described, with no significant rise in cortisol levels during the period of perfusion. In the pulsatile group, however, plasma cortisol levels rose significantly during perfusion, reaching a mean level at the end of perfusion which was highly significantly greater than that in the nonpulsatile group (p less than 0.001). Correction of the plasma cortisol values for the effect of hemodilution was performed and, again, corrected cortisol values indicated a highly significant increase in end-bypass levels in the pulsatile groups (p less than 0.001). These results clearly indicate that the reduction in cortisol secretion during nonpulsatile bypass may be prevented by the use of pulsatile perfusion.