Suture loop restriction of the medtronic hall valve: late presentation of a rare complication.

Restriction of movement of the occluder of a single disc prosthetic valve is a serious and potentially fatal complication. We present a case in which the movement of the disc of a Medtronic Hall aortic valve was restricted by a loop of aortotomy closing suture inadvertently passed around the central guide of the valve.

Involvement of the inferior vena cava by renal tumour: surgical excision using hypothermic circulatory arrest.

OBJECTIVE: To evaluate the immediate and long-term results of a radical surgical technique in the treatment of renal tumours with extensive involvement of the inferior vena cava (IVC). PATIENTS AND METHODS: Seven patients with extensive involvement of renal tumours into the IVC were operated upon using a cardiopulmonary by-pass, hypothermia and cardiac arrest to facilitate surgery. Wide exposure of the IVC in a bloodless field permitted complete removal of all visible tumour in each case. Histological sections confirmed renal cell cancer in six patients and Wilms tumour in a 15-year-old girl. RESULTS: All patients recovered well from their surgery with no major complications and spent one or two days in the Intensive Treatment Unit and an average of 13 days in hospital after the operation. Of the seven patients, four are alive and well with no obvious disease after an average follow-up time of 30 months (range 8-54). The other three patients have died from disseminated renal cancer. CONCLUSION: This procedure provides good local control of the tumour and offers the only hope of cure in patients with this disease. In collaboration with the surgical cardiac team it can be safely carried out with acceptable morbidity and mortality.

Median sternotomy wound dehiscence: a retrospective case control study of risk factors and outcome.

Over a 5-year period from 1985 to 1989, 2760 patients underwent open heart surgery at the University Hospital of Wales. Of these, 44 (1.6%, 35 men, mean age 61 years) developed median sternotomy dehiscence 2-40 (median 9) days after surgery. Infection was an associated factor in 18 patients (41%) and Staphylococcus aureus the predominant isolate in seven of those. Thirty-seven patients underwent rewiring of the sternotomy wound and seven patients underwent debridement, removal of wires and delayed closure. In those undergoing rewiring, sternal stability was maintained in 34 patients (92%). There were seven deaths (16%), of which two were considered to be wound-related. Median hospital stay of survivors was 34 (range 16-84) days. Comparison with 88 matched controls by univariate analysis showed preoperative chronic obstructive airways disease, reduced FEV1/FVC ratio (both P < 0.001) and smoking (P < 0.05) were all more common in the dehiscence group. In addition, reoperation for bleeding (P < 0.05), prolonged bypass time, postoperative ventilation period and length of stay in the intensive care unit (all P < 0.001) were more common in the study group.

Valvular and coronary artery surgery.

This brief review supplements recent extensive discussion of valvular and coronary artery surgery in this journal. It includes 1) ultrasonic decalcifications of stenotic aortic valves, a technique once more found wanting because of induced aortic incompetence; 2) the concept of prosthesis-specific anticoagulation, adjusting the level of anticoagulant control for individual prosthetic valves to minimize thromboembolic and hemorrhagic complications; 3) the use of homograft aortic roots to treat aortic prosthetic valve endocarditis; and 4) a new approach to the repair of postinfarction ventricular septal defects, supported by excellent results.

Adjusting anticoagulation to prosthesis thrombogenicity and patient risk factors. Recommendations for the Medtronic Hall valve.

In order to determine optimum anticoagulation levels for the Medtronic Hall valve, the effect of low anticoagulation (mean International Normalized Ratio [INR] 2.5, 1979-1984) and moderate anticoagulation (mean INR 3.0, 1985-1989) was determined in 345 patients (183 low, 162 moderate) undergoing isolated mitral valve replacement (MVR) and 241 patients (91 low, 150 moderate) undergoing isolated aortic valve replacement (AVR). There were no cases of valve thrombosis. Embolic events and bleeding events were graded in severity and multiple decrement event-free survival calculated according to valve site and anticoagulation level: MVR low, MVR moderate, AVR low, and AVR moderate. In the MVR low group, 80% were free of all events and 93% free of serious events at 3 years compared with 89% and 98%, respectively, in the MVR moderate group. The AVR low group experienced a very small incidence of embolic events (one only) and no bleeding events. The AVR moderate group suffered more bleeding and more embolic events and at 3 years only 87% were event-free compared with 99% in the AVR low group. In both AVR groups, all embolic events were associated with one or more known stroke risk factors. Patients under 70, in sinus rhythm who were normotensive and were nonsmokers suffered no embolic events irrespective of their anticoagulation level. We conclude that the optimum INR for the average Medtronic Hall patient is 3.0 after MVR and 2.5 after AVR but some adjustments may be required in relation to stroke risk factor analysis.

Coronary artery bypass surgery: current practice in the United Kingdom.

A survey of current clinical practice was carried out among the 84 consultant cardiac surgeons currently performing coronary artery bypass surgery in the United Kingdom. The 80 surgeons who returned the questionnaire performed an estimated total of 17,100 coronary artery bypass graft operations in 1987, a mean case load of 214 operations each. Sixty two of the 80 surgeons regarded the internal mammary artery as the graft conduit of choice, and seven preferred the saphenous vein. The internal mammary artery was used in 73% of bypass grafts to the left anterior descending coronary artery but in only 4% of grafts to the circumflex and right coronary systems. Contraindications to the use of the internal mammary artery included advanced age of the patient (51 surgeons), insufficient flow through the internal mammary artery (49), and endarterectomy (35). Seventy four of the 80 surgeons considered intraoperative damage to the saphenous vein to be a possible cause of vein graft failure, but there was no agreement about how it should be reduced. All surgeons advocated pharmacological measures to enhance graft patency. Dipyridamole and aspirin constituted the most popular regimen (58 surgeons), though only 28 started dipyridamole preoperatively. Warfarin was prescribed postoperatively on occasion by 22 surgeons, but 14 of these used it only after endarterectomy.

Post-infarction ventricular septal defect: the importance of right ventricular coronary perfusion in determining surgical outcome.

Mortality from a post-infarction ventricular septal defect (VSD) can be reduced by surgery, selection for which would be helped by knowledge of factors affecting the postoperative prognosis. We reviewed our 9-year experience (1978-1987) of 40 surgically treated patients, comparing preoperative characteristics in those who died postoperatively (n = 15, 37%) and those who survived (n = 25, 63%), all still alive. Sex, age, infarct size as assessed by peak serum creatine kinase values, left ventricular end-diastolic pressure and pulmonary/systemic flow ratio (2.9 +/- 0.2 vs 3.1 +/- 0.3) were similar. Survivors had a lower incidence of inferior infarct than those who died (6, 24% vs 9, 60%, P less than 0.05), a lower incidence of cardiogenic shock (7, 28% vs 10, 67%, P less than 0.05), less elevation of right ventricular end-diastolic pressure (10.1 +/- 0.9 vs 14.7 +/- 1.0 mm Hg, P less than 0.01) and less impairment of right ventricular coronary supply as determined by a coronary angiography-derived myocardial score (0.9 +/- 0.3 vs 4.7 +/- 0.7, P less than 0.001). The data suggest that right ventricular coronary perfusion influences prognosis. The proposed angiographic score may help to identify preoperatively those patients most likely to benefit from surgery.

Low risk of thrombosis and serious embolic events despite low-intensity anticoagulation. Experience with 1,004 Medtronic Hall valves.

One thousand four Medtronic Hall valves (601 mitral, 398 aortic, and five tricuspid) were implanted in 847 patients between December 1979 and June 1987. Total experience at the end of June 1987 was 2,640 patient-years of follow-up. Prothrombin time ratios were reviewed for all patients (16,866 observations), and these ratios were found to be therapeutically low (median international normalized ratio, 2.6) and highly variable (lower 10th percentile, 1.6; upper 10th percentile, 3.9). During the follow-up period, there were no valvular thromboses; the 95% confidence limit for the risk of thrombosis (0.14 per 100 patient-years) is below that reported for other mechanical prostheses. Sixty percent of all thromboembolic events left no residual deficit, and 75% of all bleeding events did not require treatment. Only 11% of thromboembolic events and 7% of bleeding events were fatal. The linearized rate of fatal bleeding was 0.2% per year, and the linearized rate of moderate to severe bleeding was 0.5% per year. Five-year actuarial embolic-free rates were 92%, 84%, and 83% for aortic, mitral, and double valves, respectively. The low risk of valvular thrombosis and of serious thromboembolic events in the Medtronic Hall valve, regardless of the range and variability of anticoagulation, offers greater patient safety than other mechanical prostheses, provides a credible alternative to bioprostheses, and may be particularly relevant to third-world populations.

Spontaneous closure of a traumatic interventricular septal defect following a penetrating chest injury.

A case of spontaneous closure of a traumatic ventricular septal defect following a penetrating cardiac injury is presented. The surgical management of these lesions is discussed.

Anticoagulation variability between centres: implications for comparative prosthetic valve assessment.

One of the major determinants in the choice of a mechanical prosthetic valve is that valve's thromboembolic record but the thromboembolic (TE) rates may be substantially influenced by the levels of anticoagulation achieved. A detailed study of anticoagulation variability was undertaken in 834 patients who received one or more of a particular prosthesis (Medtronic-Hall) in one centre during a 7-year period from 1979 to 1987, but who attended 27 different anticoagulant clinics spread over a wide area. In addition, a questionnaire was sent to all 89 practising cardiac surgeons in the UK asking for their preferred range of International Normalised Ratio (INR) for patients with mechanical prosthetic valves. Both the local study (with 16,866 INR observations) and the national questionnaire (with a 53% response) revealed an enormous amount of variability. Median INR values (semi-interquartile range) varied from 2.2 to 3.9 (0.8-2.5) according to the anticoagulant clinic attended. The range of INR preferred by UK cardiac surgeons, but presumably not necessarily achieved, varied from 1.8-2.2 to 3.0-4.8, with 64% of surgeons preferring an INR less than 3.0. In comparison, standard US practice is to maintain prothrombin times equivalent to INR values of 4.0-5.0. Unless anticoagulant practice can be standardised internationally, comparison of TE complications between centres is meaningless, and casts doubt on the validity of TE rates quoted for particular prostheses, unless accompanied by a detailed analysis of anticoagulant control.

Endothelial function can be preserved during cryo-storage of human saphenous vein.

Endothelial functional integrity was quantified in human saphenous vein by measurement of stimulated (vortex-mixing) rates of prostacyclin production. Prostacyclin production was not inhibited by dimethylsulphoxide (DMSO), glycerol or sucrose at concentrations normally used for cryopreservation. Rapid freezing followed by storage for 3-4 weeks and thawing of veins pretreated with 15% (v/v) dimethylsulphoxide significantly impaired prostacyclin production. In contrast, slow freezing and thawing in the presence, but not the absence, of DMSO led to complete retention of prostacyclin production. We conclude that endothelial function can be preserved during cryostorage.

Nature and pressure dependence of damage induced by distension of human saphenous vein coronary artery bypass grafts.

Surgical preparation of human saphenous vein for coronary artery bypass grafting involving distension and storage in iso-osmotic sodium chloride solution reduced tissue adenosine triphosphate (ATP) (mean(SEM] concentration from 280(20) nmol.g-1 wet wt (n = 25) to 140(30) nmol.g-1 wet wt (n = 12) and the adenosine triphosphate to adenosine diphosphate (ATP:ADP) concentration ratio from 2.4(0.1) to 1.2(0.2). Since removal of endothelium from freshly isolated vein did not affect ATP concentration or ATP:ADP ratio, these changes quantified medial damage. Distension of the vein at a pressure of 150 mmHg caused no change in ATP concentration or ATP:ADP ratio, but these values were reduced progressively by distension at 300 mmHg and 600 mmHg. Damage was not reversed but was exacerbated by subsequent incubation of the distended vein in blood. Distension of the vein at 600 mmHg caused release of tissue lactate dehydrogenase. The data show that acute medial damage can result from distension of the vein but that this does not occur at pressure equivalent to normal arterial pressure. Distension induced medial damage is unlikely to be rapidly reversible.

A surgical preparative technique for coronary bypass grafts of human saphenous vein which preserves medial and endothelial functional integrity.

Measurements of adenosine triphosphate concentration and adenosine triphosphate/diphosphate ratio provided quantitative markers for medial integrity and stimulated (vortex-mixing) prostacyclin production for endothelial function. Freshly isolated vein had an adenosine triphosphate concentration of 470 +/- 60 nmol X gm-1 wet weight and an adenosine triphosphate/diphosphate ratio of 2.50 +/- 0.13; it produced prostacyclin at a rate of 9.3 +/- 1.0 pg X min-1 X mg-1 wet weight. Vein subjected to dissection, proximal anastomosis, and distention with the patient's own arterial pressure had an adenosine triphosphate concentration of 490 +/- 70 nmol X gm-1 wet weight and an adenosine triphosphate/diphosphate ratio of 2.29 +/- 0.13; it produced prostacyclin at a rate of 10.4 +/- 2.2 pg X min-1 X mg-1 wet weight. All values were indistinguishable from those in freshly isolated vein. In vein subjected to dissection, distention at less than 300 mm Hg with patient's heparinized blood, and distal anastomosis, adenosine triphosphate concentration, adenosine triphosphate/diphosphate ratio, and prostacyclin production (5.5 +/- 0.6 pg X min-1 X mg-1 wet weight) were all significantly (p less than 0.001) reduced. These results demonstrated that surgical preparation by first proximal anastomosis preserved both medial and endothelial function.

The incidence and significance of early pericardial effusion after open heart surgery.

The presence and severity of postoperative pericardial effusions were studied echocardiographically in 114 consecutive patients (70 males, 44 females; mean age 56 +/- 10 years). An effusion was present in 35 patients at 3-5 days. An effusion was less common when a drainage tube was inserted for 24-36 h in the posterior as well as the anterior mediastinum than when only an anterior drain was used. Patients with effusions differed from those without in having more supraventricular arrhythmias, more wound infections, smaller total blood drainage and longer postoperative hospital stay. Three patients with posterior pericardial effusions developed cardiac tamponade 5-18 days postoperatively. The data show that pericardial effusions are associated with postoperative complications and suggest that effusion formation can be reduced by using posterior as well as anterior chest drains.

Preparation of human saphenous vein for coronary artery bypass grafting impairs its capacity to produce prostacyclin.

Prostacyclin production was measured from freshly isolated human saphenous vein and from vein subjected to routine surgical preparation for coronary bypass grafting. Surgical preparation had no effect on spontaneous prostacyclin production but significantly reduced stimulated rates from 16.9(1.1) to 7.1(0.5) pg.min-1 per mg wet weight (n = 27). Stimulated prostacyclin production was not reduced by storage of vein for 2 h at 23 degrees C in blood or saline nor by distension, but it was reduced to 5.0(0.6) pg.min-1 per mg (n = 10) by de-endothelialisation. Reduced prostacyclin production, which might in itself contribute to vein graft occlusion, provides a quantitative biochemical estimate of endothelial integrity.

Myxoma of the left ventricle.

We report a case of left ventricular myxoma in a 19-year-old man which presented as intermittent aortic valve obstruction. Echocardiography provided a comprehensive diagnosis, and excision through a left ventriculotomy was safely accomplished.

Malfunction of a Lillehei-Kaster aortic valve presenting as loss of the normal valve click.

We report a patient with a malfunctioning Lillehei-Kaster aortic valve which presented only as loss of the normal valve click, 7 months after temporary interruption of anticoagulation at the time of abdominal surgery. Loss of a normal prosthetic valve click may be the only sign of prosthetic valve malfunction, and it is a surgical emergency. Patients with prosthetic heart valves, who undergo non-cardiac surgery, should not receive vitamin K1, and anticoagulation should be restarted promptly after surgery with intravenous heparin as well as warfarin.