Donald Roberts

Eleven years' experience with Carpentier-Edwards biological valves in relation to survival and complications.

The Carpentier-Edwards porcine valve bioprosthesis was implanted in 299 patients (325 prostheses) from April 1976 to April 1982. The series consisted of aortic valve replacement in 150 patients, mitral valve replacement in 120, multiple valve replacement in 26, pulmonary valve replacement in 2 and tricuspid valve replacement in 1 patient. The postoperative follow-up was 100% complete. The total accumulated follow-up was 1956 patient-years. The early mortality was 6.4% (20 patients) and the late mortality was 22% (62 patients). Valve-related mortality was seen in 8 patients (2.7%): 1 paravalvular leak during the 1st 30 postoperative days and 7 late mortalities (1 endocarditis, 2 paravalvular leaks and 4 deaths during reoperation). Three operative deaths (1.5%) occurred. The overall patient survival including operative deaths was 78.5% +/- 5% at 5 years and 66% +/- 4% at 10 years. The incidence of the different complications were: thromboembolism in 5 patients (1.7%) with a risk of 0.3%, haemorrhage in 1 (0.3%) with a risk of 0.05%, endocarditis in 2 (0.7%) with a risk of 0.1%, and paravalvular leak in 11 patients (3.7%) with a risk of 0.6%. There was a high incidence of tissue failure during the last 6 years which occurred in 54 patients (18%) with a risk of 2.7%. Sixty-seven patients (22.5%) were reoperated upon during the 11 years with an annual risk of 3.4% and the main cause of reoperation was primary tissue failure. The Carpentier-Edwards biological valve was shown to be efficient during the first 5 years of implantation after which the incidence of tissue failure increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors influencing haemostasis and blood transfusion in cardiac surgery.

To find out the risk factors influencing perioperative bleeding and use of blood products in cardiac surgery so that appropriate intervent.ions can be selected for blood conservation, risk factors were analysed in 343 cardiac surgical patients, retrospectively, by multiple regression technique. The results showed that the factors related to postoperative bleeding were male gender, Higgins score, cardiopulmonary bypass (CPB) time, operation procedures, intraopera tive blood loss and use of internal mammary artery (IMA) graft. Factors related to perioperative homologous blood transfusions were emergency surgery, preoperative haemoglobin level, Higgins score, intraoperative blood loss, operation time and operation procedures. The geometric mean of postoperative bleeding in the entire series was 1085 ml and the mean packed red cell, plasma and platelet transfusions were 3.29 ± 0.4, 1.96 ± 0.39 and 0.21 ± 0.05 units respectively. The incidence of homologous blood transfusion during the hospital stay was 58.9% for the entire series and 54.5% in the nonrevision patients. Emergency patients received significantly more blood transfusion (p = 0.0001). Perioperative blood loss and transfusions are still problems in cardiac surgery and certain patient groups in this study were identified as high risk; available blood conservation techniques, therefore, are recommended in these patients.

Long-term follow-up of operative treatment for pulmonary metastases

From 1954 onwards, 132 patients underwent 165 resections for pulmonary metastases. No other forms of therapy were adopted. The operative mortality was 7.6% (10 patients). After a minimum follow-up of 5 years, the overall survival rate was 20%. The 10- and 15-year survival rates were 6% and 3%, respectively. The major cause of late death was recurrence or spread of the primary disease in 102 patients (83.6%) while 5 patients died of reasons not related to cancer. Fifteen patients (12.3%) are still alive, 13 of whom have no clinical cancer. The presence of symptoms, the disease-free interval of less than 1 year and the number of metastases showed a statistically significant detrimental influence on survival (P less than 0.001, P less than 0.05 and P less than 0.046, respectively). The best 5-year survivals of 42%, 24%, 23% and 23% were noted for metastases from malignancies in the body of the uterus, kidney, bone and colon, respectively. Longterm survival or clinical cure can be achieved with surgery alone by an aggressive approach in selected malignancies.

The influence of age on the durability of Carpentier-Edwards biological valves Thirteen years follow-up

Two hundred and ninety-nine patients received 325 Carpentier-Edwards biological valves from April 1976 to April 1982. Valves were placed in the following positions: 150 aortic (AVR), 120 mitral (MVR), 26 multiple (MR), 2 pulmonary (PR) and 1 tricuspid (TR). The mean age was 54.7 years. The total follow-up time was 2545 patient-years. Patients were divided into different age groups: less than 40, 40-49, 50-59, 60-69 and greater than 70 years and were followed-up for reoperations and tissue failure. Ninety-three operations were performed in 91 patients (30.5%) for valve related dysfunctions. The main cause of reoperation was primary tissue failure (85%). The respective incidence and risk of reoperation in the different age groups were 51.5% and 5%, 41.5% and 4%, 32% and 3%, 18% and 2.5%, and 0% for greater than 70 years of age. The risk of reoperation decreased significantly with increasing age (P less than 0.05). The respective incidence and risk of tissue failure in the age groups were 43.8% and 4.1%, 35% and 4%, 27.3% and 3.2%, and 17.2%, 2.4% and 0%. The freedom from reoperation and tissue failure was significantly higher in the older patient (greater than 60 years) compared to the younger patients (less than 60 years). The commonest cause of failure in young patients was calcification, while in older patients it was cusp rupture. Comparing aortic and mitral bioprostheses in the different age groups showed no difference between these valves in patients less than 50 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

The Effect of Urea on Red Cell Deformability During Cardiopulmonary Bypass

Red cell deformability was measured from the red cell filtration rate (RFR) in 33 patients undergoing cardiopulmonary bypass (CPB). Urea (1.0 g/kg b.w.) was given to 14 of the patients and 19 were controls in a prospective, blind study. The mean RFR (microliters/s) fell during 120 min of CPB, from 36.8 to 11.2 in the control group and from 37.4 to 25.0 in the urea group. In 17 patients undergoing single valve replacement, the mean RFR at CPB time 120 min had fallen from 38.5 to 17.4 in the controls and from 38.0 to 30.0 in the urea group. The corresponding figures in the 16 patients who underwent coronary bypass graft procedures were 35.0 to 3.5 (controls) and 36.8 to 20.8 (urea). The study confirmed the deleterious effect of CPB on the red cell and showed that this damage can be significantly reduced by administration of urea.

Surgical Removal of Pulmonary Metastases from Renal Cell Carcinoma

Thirty-three patients operated on for pulmonary metastases from renal cancer were followed up for a minimum of 5 years or to death. The 5-year survival was 21%. There was a tendency to better survival in patients operated by lobectomy rather than limited resection. Extended operations carried a grave prognosis. Manifest metastatic disease within one year after the primary operation showed shortened survival. Repeated operations were possible, with good results. It is concluded that operations for pulmonary metastases can be performed with good results. However, the effect is a palliative one as the ultimate cause of death in all instances was the spread of the cancer disease.

Hepatic Dysfunction After Open-Heart Surgery

In a prospective study, 93 patients were observed up to nine months after open-heart surgery using hypothermia, hemodilution and cold cardioplegia. In the first two weeks frequent determinations were made of serum aminotransferase, alkaline phosphatases (ALP), lactic dehydrogenase isoenzymes, gamma glutamyltransferase (GT), total and free bilirubin and bile acids. Plasma hemoglobin was measured at the end of the operation. After the first period, aminotransferases, alkaline phosphatases and bilirubin were determined monthly. On the first postoperative day almost all of the patients showed abnormal aspartate aminotransferase (ASAT) activity and ASAT/ALAT (alanine aminotransferase) greater than 1, and about 25% had hyperbilirubinemia. The findings suggested early postoperative leakage of enzymes not only from the myocardium, but also from the liver. After two weeks the patients presented another pattern of liver dysfunction, with abnormal ALAT in 50%, ASAT/ALAT less than 1, and abnormal ALP and GT in 28 and 45%, respectively. Eight patients were judged to have post-transfusion hepatitis of non-A, non-B type. Six of them had abnormal aminotransferases for more than six months.

Changes in red cell deformability associated with anaesthesia and cardiopulmonary bypass in open-heart surgery

Red cell deformability was observed during open-heart surgery in 59 patients. Deformability, assessed with a standard microfiltration method, was expressed as red cell filtration rate (RFR) in microliter/s. The mean preoperative value, 38.9 +/- 1.0 microliter/s, showed a generally falling tendency. The first significant decrease in mean RFR (by 18%) followed induction of general anaesthesia, and the second (by 15%) was seen 60 min after the start of cardiopulmonary bypass (CPB). The major decrease in RFR during CPB was found at the end of bypass, when it was reduced to 62% of the pre-CPB value. The percentage RFR reduction at the end of CPB showed significant correlation with 1) CPB duration (r = 0.49), 2) oxygen flow rate index (OFRI), i.e. flow/min in the bubble oxygenator/m2 bsa (r = 0.38), and 3) blood flow rate index (BFRI), i.e. average volume of blood pumped through the heart-lung machine/min CPB time/m2 bsa (r = 0.51).

Evaluation of Red Cell Damage During Cardiopulmonary Bypass

In patients undergoing cardiopulmonary bypass (CPB), red cell damage was assessed by simultaneous measurement of of plasma-haemoglobin (P-Hb) and red cell filtration rate (RFR) (1). RFR was significantly reduced after 120 min as compared with 30 min (17.4 +/- 4.1 vs. 30.4 +/- 2.9 microliters/s). P-Hb, by contrast, was significantly higher at 60 min than at 30 min after start of CPB (195 +/- 27.2 vs. 73.8 +/- 8.1 microliters/s). Significant negative correlation was found between RFR and P-Hb (r = 0.68). Red cell deformability thus permitted qualitative assessment of red cell trauma during CPB and thereby an estimation of the rheologic disturbance caused to these cells by CPB during open-heart surgery.

Cutaneous microcirculation and blood rheology following cardiopulmonary bypass: laser Doppler flowmetric and blood cell rheologic studies

In 23 patients undergoing coronary artery bypass grafting, measurements of cutaneous blood flow were made with laser doppler flowmetry. Simultaneously blood was sampled for measurement of red cell filtration rate (RFR) and plasma-white cell filtration rate (P-WFR). The cutaneous blood flow showed significant overall reduction postoperatively. When the saphenous vein or internal mammary artery was used as bypass graft, the reduction in skin blood flow at the sites from which the vessels were taken was significantly greater than in contralateral, undisturbed sites. RFR and P-WFR were also significantly reduced postoperatively, and these changes showed significant concomitance with the fall in laser doppler flow (LDF%). On postoperative day 6 there was some improvement in LDF% and RFR but further slight deterioration in P-WFR. The study indicated that surgical trauma locally reduces cutaneous blood flow and that trauma to blood cells following cardiopulmonary bypass can contribute to this reduction.