The activated clotting time loading dose response ratio (ACTLORR) as an indicator of heparin demand during cardiopulmonary bypass.

Data relating to the activated clotting time response to a 4 mg/kg heparin loading dose were collected prospectively in 358 patients having cardiopulmonary bypass. After excluding patients with factors known to cause relative heparin resistance or sensitivity, the activated clotting time (ACT) loading dose response ratio (ACTLORR) was calculated retrospectively in 263 patients and found to correlate significantly (p = 0.0001) with the need for extra heparin administration during bypass. Where the ACTLORR was above 5.5, 92% of patients required no additional heparin during the first 90 minutes of bypass (n = 98). Where the ACTLORR was between 4.0 and 5.0, it was far less predictive, with approximately 35% of patients requiring additional heparin. This study indicates that a large ACT response to the initial heparin loading dose (a high ACTLORR) is predictive of stable, adequate anticoagulation during the first 90 minutes of bypass, but that a low initial response is not necessarily associated with declining ACTs and the need for additional heparin administration.

Muscle tamponade to control venous bleeding around grafts to deeply intramyocardial coronary arteries.

Considerable difficulty may be encountered in controlling persistent venous bleeding from the cut myocardial edges when coronary grafts have to be constructed to a deeply intramyocardial portion of the left anterior descending coronary artery. We describe a safe, inexpensive, and highly effective method of dealing with this problem using muscle tamponade with a prepared segment of rectus abdominis muscle. The technique has been used with uniform success and without complication in more than 60 patients.

Re-inventing the wheel; the use of autologous and fresh donor blood in cardiac surgery.

From the opening of a new cardiac surgical programme in November 1992, autologous and fresh donor blood (FDB) were used rather than cold stored blood (CSB) wherever possible in patients undergoing operations involving the use of cardiopulmonary bypass (CPB). In the first 250 consecutive patients, autologous blood was used in 168 (67.2%), fresh blood was used in 188 (75.2%). A total of 740 units of fresh blood were obtained on the day of operation (mean 3.9 +/- 1.6 units per patient able to supply donors; 4.9 +/- 1.7 units in the 147 who received fresh blood) and 728 units of stored blood were used (mean 3.08 +/- 1.84 units per patient where fresh blood was used; 6.2 +/- 2.5 units in the 114 where no fresh blood was used). The use of autologous blood significantly reduced FDB and CSB requirements (p < 0.001), was associated with a shorter intensive care and total postoperative stay (p = 0.006 and p = 0.033 respectively), even though there were more urgent and emergency cases in this group (p = 0.009) and no significant difference in chest drainage. Coagulopathy developed in 41 patients (16.4%) and was significantly associated with bypass time (p = 0.0001) and preoperative renal dysfunction (p = 0.005), although not with advanced age, sex, redo operation, diabetes or glucose-6-phosphate dehydrogenase deficiency. Patients with coagulopathy had significantly more transfused blood and blood products (p = 0.0001) and longer intensive care and total postoperative stays (p = 0.0001). In terms of blood conservation, the use of autologous blood was of primary importance.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary clinical experience with the Jyros bileaflet mechanical prosthesis.

The Jyros bileaflet mechanical prosthesis is unique among bileaflet valve designs in that there is no fixed hinge mechanism and after implantation, the leaflets are free to rotate as determined by blood flow through the orifice. Between November 1992 and April 1994, 56 Jyros valves were implanted in 44 patients at 45 operations. There were 31 males and 13 females (ratio 2.3:1), with a mean age of 3714 and a range owelve patientsplacement (AVR) (26.7%), 19 had mitral valve replacement (MVR) (42.2%), and 14 had AVR plus MVR (DVR) (31.1%). In three DVR patients the Jyros valve was implanted only in the mitral position. There was one hospital death following DVR (2.3% mortality). Total follow-up of 341 patient-months (28.4 patient-years) is 100% complete. There were no late deaths. There was one reoperation for acute mitral prosthetic thrombosis (3.5%/patient-year). Another Jyros valve was inserted; leaving 53 valves at risk in 42 patients at the close of follow-up. There were no episodes of thromboembolism, transient ischemic attacks, endocarditis, hemolysis, or valve dysfunction, but three patients had four episodes of anticoagulant-related hemorrhage. Echocardiographic follow-up data was available in 29 patients and indicated satisfactory hemodynamic performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycotic aneurysm of the left anterior descending coronary artery after aortic endocarditis. A case report and brief review of the literature.

This report concerns a 29-year-old man with recent Streptococcus viridans endocarditis on a bicuspid aortic valve who was found to have a mycotic aneurysm of the left anterior descending coronary artery and infective erosion and thinning of the posterior wall of the ascending aorta 1.5 to 3.5 cm above the origin of the left coronary artery, a combination of lesions not previously reported. Mycotic aneurysm of the coronary arteries affects less than 1% of patients with infective endocarditis, and there are few reports of the management of these rare lesions. The surgical management of this patient is presented with a brief review of the available literature.

Serum C reactive protein in infective endocarditis.

C reactive protein (CRP) was measured serially in 29 patients with infective endocarditis. Twenty one patients were initially treated with antimicrobial drugs. In 13, serial measurement of CRP concentrations showed a progressive return to normal (less than 10 mg/l), which correlated with a satisfactory recovery. Of the remainder (eight patients), five had persistently high concentrations of CRP, indicating a failure to respond to antimicrobial treatment alone. Two of these five patients died and three underwent valve replacement. Of 11 patients treated with antibiotics and valve replacement, CRP concentrations returned to normal in nine. Two patients had infective complications and the CRP concentration did not return to normal. A transient rise in CRP concentration during an otherwise uneventful fall to normal was a sign of allergic reaction in two and of intercurrent infection in three more patients. Serial measurements of CRP concentrations in patients with infective endocarditis may be useful to monitor treatment and also to detect other infections and complications.

Primary tissue failure in pericardial heart valves.

A number of centers have recorded a significant incidence of primary tissue failure with the standard Ionescu-Shiley pericardial valve. In most cases severe regurgitation was caused by leaflet tears adjacent to the edge of the cloth-covered stent. Our early clinical experience (up to 4 years' follow-up) with two new pericardial valves (Ionescu-Shiley low-profile and Hancock pericardial valves) has shown that primary tissue failure also occurs in these new valves. In vitro accelerated fatigue studies on seven of these valves (size 29 mm) showed that in vitro premature leaflet failure was caused by abrasion of the leaflet on the cloth-covering at the edge of the stent. Clinically, endothelialization and host tissue ingrowth on the cloth and the leaflets at the edge of the frame greatly reduced the amount of abrasion and the incidence of tissue failure. In seven of the eight explanted valves studied, leaflet tears occurred at the top of the stent posts where there was less endothelialization and tissue ingrowth, close to the points where sutures pass through the leaflets. It is likely that both abrasion and stress concentration around these sutures contributed to the tissue failures in the clinical valves.

Rapid diagnosis of an outbreak of Legionnaires' disease at Glasgow Royal Infirmary.

In the last three months of 1985 there was an outbreak of legionnaires' disease at Glasgow Royal Infirmary affecting 15 patients and one surgeon; five patients died. Legionnaires' disease was first suspected when a second case of severe nosocomial pneumonia occurred in a high dependency unit. The application of the direct fluorescent antibody test to specimens obtained at bronchoscopy was responsible for the rapid diagnosis of legionnaires' disease, which led to the prescription of appropriate antibiotic treatment and the shutting down of the contaminated cooling tower, thereby containing the outbreak. It also led to a search for further cases. It is suggested that these diagnostic techniques should be included in the investigation of affected patients in an outbreak of pneumonia.

Recent clinical experience with percutaneous intra-aortic balloon pumping.

From January 1984 to August 1985, 51 out of 2138 patients undergoing cardiac surgery (2.38 per cent) had an intra-aortic balloon pump (IABP) inserted or an attempted insertion. The patients ranged in age from 24 to 68 years (mean 54.2 years). An IABP was inserted preoperatively in four patients, all of whom were in cardiogenic shock; peroperatively in 27 patients who could not be weaned from cardiopulmonary bypass; and postoperatively in 16 patients who had haemodynamic deterioration. Failed insertion occurred in a further four patients. Twenty-eight patients (59.6 per cent) had percutaneous insertion of the balloon, in 17 (36.2 per cent) the common femoral artery was exposed prior to insertion and in two (4.2 per cent) the balloon was inserted into the thoracic aorta. The overall survival rate was 38.3 per cent for patients with successful insertion. Major complications that threatened life or limb occurred in 10.25 per cent of patients. These complications were confined to females and in these patients the percutaneous technique for inserting intra-aortic balloons should be used with caution.

Non-invasive assessment by Doppler ultrasound of 155 patients with bioprosthetic valves: a comparison of the Wessex porcine, low profile Ionescu-Shiley, and Hancock pericardial bioprostheses.

One hundred and fifty five patients with 167 bioprosthetic valves (68 Wessex porcine, 54 Hancock pericardial, and 45 low profile Ionescu-Shiley pericardial valves) were studied by Doppler ultrasound. Valve gradients were calculated from the mitral and aortic flow velocities by the modified Bernoulli equation. Mean mitral gradients were significantly smaller across the Ionescu-Shiley valves than across the Wessex porcine or Hancock pericardial valves. Mitral pressure half time was, however, significantly longer in the Hancock pericardial than in the Wessex porcine or Ionescu-Shiley valves. No significant differences were seen among the groups of aortic bioprostheses, though the comparable size of Wessex porcine valves showed significantly higher gradients. Bioprosthetic regurgitation was detected in 13 of 103 mitral and 11 of 59 aortic valves, though it was suspected clinically in only 12 mitral and six aortic bioprostheses. Doppler ultrasound is a repeatable non-invasive method of acquiring haemodynamic information in vivo from a variety of bioprostheses and it can detect bioprosthetic regurgitation at an early stage.

In vitro evaluation of six mechanical and six bioprosthetic valves.

The in vitro function of 6 tissue valves and 6 mechanical valves (all size 29) was assessed in a purpose-built pulse duplicator under different pulsatile flow conditions. Valve function was analyzed by measuring the mean pressure difference across each valve during forward flow, and the reverse flow through each valve during valve closure (dynamic regurgitation) and in the fully closed position (static regurgitation). Although valves of the same type showed similar characteristics, there were significant differences in function between different types of valves. Porcine valves showed much higher forward flow pressure gradients than pericardial, tilting disc, or bileaflet mechanical valves. However, the porcine valves showed least regurgitation, with pericardial valves having less regurgitation than mechanical valves.