Transcatheter closure of a complex postmyocardial infarction ventricular septal defect after surgical patch dehiscence.

Ventricular septal defect (VSD) complicating acute myocardial infarction is a rare but serious event carrying a high mortality. Residual shunting after emergency surgical repair is common, adversely affects prognosis and can necessitate reoperation. We describe the successful transcatheter VSD closure with the Amplatzer occluder in a 75-year old man after earlier emergency surgical repair of a VSD complicating an acute myocardial infarction. The technique and positioning of the device in a tortuous infero-apical VSD are described.

Thrombotic risk in patients with aortic bioprostheses.

Thrombosis of Mosaic aortic valve bioprostheses occurring at more than one month after surgery occurs in 0.8% (95% CI 0.33-1.67%) of patients. In the two cases reported here, each patient had risk factors for thrombus formation, namely severe left ventricular impairment in one patient, while the other patient was heterozygous for prothrombin variant G20210A. The cases were treated successfully, by thrombolytic therapy with streptokinase in the first case, and by repeat aortic valve replacement in the second case. Thrombosis of bioprosthetic valves in the aortic position is rare, and a period of anticoagulation postoperatively does not invariably protect against this serious complication. In conclusion, patients with risk factors for thrombus formation should be considered for long-term anticoagulation.

Enoxaparin treatment in women with mechanical heart valves during pregnancy.

OBJECTIVE: This prospective audit reports pregnancy outcomes, anticoagulation complications, and anti-Xa levels in women with mechanical heart valves who were treated with therapeutic enoxaparin plus aspirin during pregnancy. STUDY DESIGN: Between 1997 and 1999, 11 women with mechanical heart valves were treated with enoxaparin, 1 mg/kg twice daily, and aspirin, 100 to 150 mg daily during 14 pregnancies. Predose and 4-hour postdose anti-Xa levels were monitored monthly. RESULTS: There were 9 live births, 3 miscarriages, and 2 terminations. In 48 months of enoxaparin treatment, one woman who had a documented valve thrombosis when she presented at 8 weeks' gestation also had a valve thrombosis at 20 weeks' gestation. There were no enoxaparin-related hemorrhagic complications. Mean (SD) anti-Xa levels were 0.46 (0.12) U/mL predose and 0.89 (0.22) U/mL 4 hours postdose. CONCLUSION: Successful pregnancy outcome may be achieved with therapeutic subcutaneous enoxaparin, but its efficacy at preventing valve thrombosis remains uncertain. Further data are required before use of enoxaparin during pregnancy in women with mechanical heart valves can be recommended.

Initial experience with the freestyle stentless aortic bioprosthesis.

AIMS: We report our initial experience with the Freestyle aortic bioprosthesis. METHODS: This prosthesis was implanted in 40 patients between February 1993 and December 1998. Operative indications were aortic stenosis in 32 patients (80%), aortic regurgitation in seven patients (18%) and a combined lesion in one (3%). The mean patient age was 71.4+/-9.7 (SD) years, with 29 (72%) females. Pre-operative New York Heart Association (NYHA) class was III or IV in 28 (70%). Left ventricular systolic function was impaired in four (10%). Six (15%) patients had undergone previous cardiac surgery. Concomitant procedures were carried out in 21 patients (53%). RESULTS: Early mortality was zero. Early morbidity included three re-operations for bleeding, one cerebrovascular event, one haemorrhagic complication and one case of valve dysfunction. At follow up (range 4.6 to 75.6 months, mean 29.5+/-25.5) there has been one (3%) late death which was non valve related, one (3%) episode of study-valve endocarditis, and three (8%) thromboembolic episodes. NYHA Class was I or II in all but one survivor. Echocardiographic follow-up has shown no further instances of valve dysfunction with satisfactory haemodynamic parameters at 24-months post-operation, and a significant and sustained regression of left ventricular mass. CONCLUSIONS: The initial experience with the Freestyle valve is that it results in good clinical and haemodynamic performance, suggesting it as an ideal bioprosthesis for this patient group.

Early experience with the mosaic bioprosthesis: a new generation porcine valve.

BACKGROUND: The Mosaic bioprosthesis is a new generation stented porcine valve. METHODS: Between May 1995 and April 1998, this valve was implanted in the aortic position in 98 patients (70 men; mean age, 69.2 years [34.2 to 83.6 years]). Preoperatively 35 patients were in New York Heart Association functional class 3 or 4. Fifty-nine patients underwent concomitant procedures. The mean duration at follow-up in January 1999 was 23.7 +/- 10.2 months (0.3 to 39.4 months) and totaled 193 patient-years. All but one survivor was in New York Heart Association class 1 or 2. RESULTS: Early complications included 1 death, 3 reoperations for bleeding, greater than mild regurgitation (paravalvar) in 1 patient and thromboembolism in 4 patients. Late complications included four deaths, study-valve endocarditis in 3 patients, more than mild regurgitation or hemolysis in 2, and thromboembolism in 2 patients. Late follow-up echocardiography in all survivors showed a mean transaortic gradient of 13.6 +/- 6.7 mm Hg, and an aortic valve area of 1.80 +/- 0.61 cm2. Valve replacement was followed by a significant and sustained decrease in left ventricular mass for all valve sizes. There has been no primary structural valve failure. CONCLUSIONS: The early experience with the Mosaic valve in the aortic position has been promising.

Transposition of the great arteries: operative outcome in the current era.

AIMS: To assess the operative outcome, cardiac and neurodevelopmental sequelae in infants with transposition of the great arteries (TGA) undergoing the arterial switch operation (ASO). METHOD: Cross-sectional review of the 48 consecutive patients operated on in the calendar years 1995 and 1996 was undertaken to obtain recent cardiac, growth and neurodevelopmental parameters, and the mortality results were compared to the entire cohort of infants who underwent the ASO for definitive repair of TGA and double outlet right ventricle at Greenlane hospital between 1984 and 1998. RESULTS: Between January 1995 and December 1996, 48 patients underwent the ASO. 96% were alive, and 88% alive and free from reoperation or significant neurological sequelae at a mean followup interval of sixteen months. Six (13%) had important residual cardiac lesions, of which supra valvular pulmonary stenosis was the most common. Growth parameters at follow-up were normal, as was the neurodevelopmental progress of all but two survivors (96%). CONCLUSION: In the current era, the ASO is a relatively safe procedure with excellent cardiac and neurodevelopmental outcome in the majority of infants.

Green Lane Hospital experience with mitral valve repair for prolapse: adverse outcomes for highly symptomatic patients.

BACKGROUND AND AIMS OF THE STUDY: Valve repair, where suitable, is the preferred option in patients who require mitral surgery. A number of studies have shown excellent long-term results, but most were undertaken in tertiary referral centers with a high throughput of patients. METHODS: We present our experience in 60 patients, aged 60 +/- 14 years, undergoing repair between 1984 and 1993. Most patients (83%) were in New York Heart Association (NYHA) class II or III at the time of surgery; 27% had concomitant ischemic heart disease. Almost all (98%) had posterior leaflet repair and 18% had anterior leaflet repair. Eight surgeons each performed a mean of 7.5 operations during this period. RESULTS: The 30-day mortality rate was 3.3%. There were seven late deaths. Five patients underwent reoperation for mitral regurgitation (two early, three late). At six years, 60% of patients were alive, or free of stroke or reoperation. Late follow up was obtained in 45 of 47 surviving patients: 95% were in NYHA class I or II; one-third were on anticoagulants for atrial fibrillation; 90% had mild (or less) mitral regurgitation on echocardiography. CONCLUSIONS: These data show that most patients have a very good outcome from valve repair surgery and encourage the trend towards operating earlier in the course of the disease. Adverse outcomes occurred mainly in patients who were highly symptomatic at the time of surgery. The high proportion of patients on postoperative anticoagulants underscores the importance of operating before atrial fibrillation becomes permanent.

Surgical correction of hypertrophic obstructive cardiomyopathy: seventeen-year Green Lane experience.

Between 1977 and 1994, 42 patients were treated surgically for hypertrophic obstructive cardiomyopathy (HOCM). Patients have been followed up between 2 months to 17 years, mean of 107 months. There were 26 (62%) males and 16 (38%) females. There was only one pediatric case. There was no correlating factor among the ethnic groups (Maori, European, Indian, Asian, etc.). Family history was noted in 12% of the cases. Seventy-one percent of patients had aortic/left ventricular (LV) combined approach while 29% had aortic approach alone at the time of surgery. Five patients underwent other procedures, along with coronary artery bypass grafting in 3, mitral valve replacement in 1, and aortic valve replacement in 1. Persistent postoperative arrhythmias were found in 7 cases, atrial fibrillation (AF) in 3, and left bundle branch block in 4.

The stentless bioprosthesis: surgical challenges and implications for long-term durability.

An attempt is made to analyse the factors which are expected to influence clinical results following implantation of a stentless porcine bioprosthesis. Long experience with implantation of allograft aortic valves provides a meaningful basis for comparison with a glutaraldehyde-fixed device. Morphological differences between the two valves involve the aortic wall and muscle shelf, and differences in valve preparation include the strength and stiffness of the aorta and the extensibility of the valve leaflets. As a result of these differences, sizing of the porcine valve is expected to be more critical than the allograft valve and the porcine valve is also expected to be more obstructive. Methods for reducing the obstructive element include the use of a composite aortic valve, a porcine pulmonary valve, or a valve in which the aorta is glutaraldehyde-fixed under pressure while the leaflets are pressure-free. The techniques available for implantation, namely freehand insertion, total root replacement and mini-root replacement, are examined.

Truncus arteriosus with type B interrupted aortic arch: correction in the neonate.

Two neonates with truncus arteriosus (TA) and type B interrupted aortic arch are reported. In both, a homograft was used to connect the right ventricle to the pulmonary artery, while the arch continuity was established by direct anastomosis of the aortic arch to the descending aorta.

Surgical treatment of the ascending aorta. Fourteen years' experience with 83 patients.

Between December 1972 and December 1986, 83 patients with aneurysmal disease (n = 37) or dissection (n = 46) involving the ascending aorta underwent a variety of operations, including composite value-graft repairs (n = 39), separated replacements of the aortic valve and ascending aorta (n = 18), resuspension and graft replacement of the ascending aorta (n = 9), graft replacement of the ascending aorta only (n = 8), homograft root replacement (n = 3), aortic valve replacement with aortorrhaphy (n = 3), aotorrhaphy alone (n = 2), and use of a sutureless intraluminal prosthesis (n = 1). The inclusion method was used in nine patients. The hospital mortality rate was 10% for patients with annuloaortic ectasia, 21% (70% confidence interval 13% to 30%) for acute dissection, and 18% (70% confidence interval 14% to 22%) for the entire group. Logistic regression analysis showed age and cumulative bypass time to be significant for hospital death. The estimated 5-year survival rates are 69.5% +/- 7.2% and 67.0% +/- 9.0% and 10-year estimates are 34.6% +/- 10.6% and 61.4% +/- 9.8% for dissection and aneurysm, respectively. Patient survival was related to differing pathology and type of operation, and log-rank testing showed no differences at the 5% level. Attrition (17 late deaths) was mostly due to left ventricular dysfunction, myocardial infarction, or aneurysmal disease in ungrafted aorta. Actuarial freedom from thromboembolism in patients with prosthetic valves is 92.0% +/- 4.0% and 83.5% +/- 6.8% at 5 and 10 years. Freedom from all late graft and cardiac complications is 72.5% +/- 9.1% and 48.8% +/- 13.1% at 5 and 10 years for aneurysmal disease and 79.1% +/- 7.3% and 67.3% +/- 9.9% at 5 and 10 years for dissection. Reoperation in nine patients was required for pseudoaneurysms (n = 3), other aortic aneurysms (n = 3), persistent aortic regurgitation (n = 1), and obsolescent valve prosthesis (n = 2). Thus hospital mortality does not seem to be significantly related to the type of operation used for pathologic conditions of the ascending aorta unless cumulative bypass time exceeds about 2 hours. Many nonfatal late complications are associated with a prosthetic valve, but late death is due primarily to cardiac causes and residual disease in other parts of the aorta.

Rupture of a calcified true left ventricular aneurysm: echocardiographic diagnosis and successful repair.

This report describes a rupture of a calcified left ventricular aneurysm 10 years after initial infarction. Operation 10 days after rupture was complicated by extensive ventricular calcification, in particular, the ventricular septum. Repair was achieved by endocardial resection of calcium, preservation of the myocardium and linear approximation.

The surgical anatomy of the rectum--a review with particular relevance to the hazards of rectal mobilisation.

The major complications of rectal surgery that are wholly or partially avoidable by the use of an anatomically based dissection are haemorrhage from presacral veins, perforation of the rectum, damage to pelvic autonomic nerves and inadequate clearance of a rectal cancer. Important technical points in minimising the incidence of these complications are: (1) posterior dissection in the presacral space; (2) entry to this space by sharp dissection immediately posterior to the superior rectal artery; (3) deliberate incision of the rectosacral fascia; (4) anterior dissection posterior to Denonvilliers fascia in benign disease; (5) removal of the entire mesorectum for low rectal cancer. Other anatomical points not widely appreciated are: 1. The middle rectal artery does not run in the lateral ligaments of the rectum, but below them, on levator ani. It reaches the rectum by penetrating Denonvilliers' fascia. 2. The lateral ligaments may contain an accessory middle rectal artery in 25% of cases. 3. The pelvic autonomic nerves are buried in endopelvic fascia on the pelvic side wall, but come to lie close to the anterior aspect of the rectum at the level of the prostate or upper vagina.

Intussusception: analysis of 98 cases.

A retrospective study of the clinical features and surgical management of 98 cases of paediatric intussusception treated in New Zealand during the past 16 years is presented. The classic triad of vomiting, rectal bleeding and abdominal pain occurred in only 20 percent of patients. Barium enema examination was used in 67 patients but successful reduction was achieved in only 13. Laparotomy was performed in 85 patients with 1 operative death. Gangrenous bowel was found in 17 patients and 24 required bowel resection with no associated mortality. This high rate of bowel resection appears to be related to the long duration of symptoms before the diagnosis was established. It is concluded that earlier diagnosis is the single factor most likely to reduce morbidity.

Choledochal cyst: a review of seven cases from Auckland.

This is a short review of the operative experience during the last decade with seven patients who presented with a choledochal cyst. A choledochal cyst is reported for the first time in a Polynesian. The relevant literature is briefly reviewed, with particular attention to operative management, which was found to carry a 10% mortality.