Malcolm Dalrymple-Hay

Aortic valve replacement in children: are mechanical prostheses a good option?

OBJECTIVE The choice of the most appropriate substitute in children with irreparable aortic valve lesions remains controversial. The aim of this study was to assess early and late outcomes following aortic valve replacement (AVR) with mechanical prostheses in children. PATIENTS Fifty-six patients (42 male, 14 female, mean age 11.2, range 1-16 years) undergoing AVR with mechanical prostheses between October 1972 and January 1999 were evaluated. Thirty-six patients (64.2%) underwent previous cardiac surgery. Disease aetiology was congenital in 47 patients (congenital aortic stenosis in 33, and other congenital abnormalities in 14) (83.9%), infective in four (7. 1%), rheumatic in two (3.4%), and three (5.3%) had connective tissue disorders. Haemodynamic indication for AVR was aortic regurgitation (AR) in 24 (42.8%), aortic stenosis (AS) in 22 (39.2%) and mixed disease in ten (17.8%). Twenty-eight patients (50.0%) were in New York Heart Association (NYHA) class III-IV before surgery. Concomitant procedures were performed in 31 patients (55.3%), including aortic root enlargement in 28 (50%). The mean size of implanted valves was 22.4 mm (range 17-27 mm). All patients received long-term anticoagulation treatment with sodium warfarin, aiming to maintain an international normalized ratio (INR) between 2.5-3.0. The mean follow-up was 7.3 years (range 0-26, total 405 patient-years). RESULTS Operative mortality was 5.3% (three patients). Three patients developed complete heart block requiring pacing, two of them permanently. Late events included valve thrombosis (one), transient stroke (one), paravalvular leak of a mitral prosthesis (one), aneurysm of sinus of Valsalva (one) and pannus ingrowth (one). There was no major haemorrhagic event. Five patients required re-operation (8.9%), but none due to outgrowth of the valve. Regarding actuarial freedom from thrombo-embolism, any valve-related event and re-operation at 20 years was 93, 86.6 and 86. 4%. There were three late deaths. Actuarial survival, including operative mortality, at 10 and 20 years was 91 and 84.9%. The actuarial survival for the group of the patients with congenital AS (n=33) at 10 and 20 years was 93.5%, whereas for the children with other congenital heart problems (n=14) this was 85.7 and 64.3% (P=0. 09). At the latest clinical evaluation, 44 children were in NYHA class I and six were in class II. The mean gradient across the aortic prosthetic valve on echocardiography was 17.9 mmHg (range 0-47 mmHg). CONCLUSIONS Mechanical AVR, with enlargement of the aortic root if necessary, remains an excellent treatment option in children. It is associated with acceptable operative mortality, low incidence of late events and re-operation, and provides good long-term survival. It clearly represents a good alternative to available biological substitutes, including the pulmonary autograft (Ross procedure).

Cardiac surgery in the elderly.

OBJECTIVE There has been a gradual increase in the number of elderly patients referred for cardiac surgery. These patients present a difficult challenge, they are usually symptomatic yet at high risk for intervention. The aim of this study is to review our experience with cardiac surgery in patients aged 80 years or older. PATIENTS AND METHODS Between January 1981 and October 1997, 242 patients; 135 female, 107 male, mean age 82.8 years (range 80-95) underwent surgery on cardiopulmonary bypass in our unit. Surgery was performed on 14 as an emergency and 136 on an urgent (patient restricted to a hospital bed due to symptoms) basis. Pre-operatively 182 (75.2%) were in NYHA functional class 3 or 4. RESULTS Early mortality was 14 (5.7%). A mitral valve procedure and emergency surgery were significantly associated (P < 0.05) with an increased risk of operative mortality. Median ITU and in-hospital stay was 1 day (range 0-33) and 10 (range 6-49) days, respectively. Ninety-three percent of patients were living independently at home 2 months post-operatively. Survival (+/-SEM) is 98% complete (totals 557 patient years) and including early mortality at 1 and 5 years was 85.5+/-2.4% (n = 154), and 67.7+/-4.3% (n = 33). Survival for patients undergoing isolated aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) at 5 years was 64.8+/-7.8% and 79.7+/-7.4%, respectively. Survival was significantly worse in patients undergoing a mitral procedure. Using Coxs proportional hazards model only type of operation (mitral surgery) was significantly associated with worse survival. CONCLUSION Cardiac surgery can be performed in a selected elderly population with a low operative mortality. Post-operatively elderly patients attain an excellent quality of life and survival. Emergency and mitral surgery in this group of patients is less rewarding.

Open Commissurotomy for Critical Isolated Aortic Stenosis in Neonates

BACKGROUND The optimal management of critical aortic stenosis in early infancy remains controversial. The aim of this study was to assess the early and late outcomes following open surgical valvotomy for critical aortic stenosis in neonates and to provide a framework of data against which current results of other treatment approaches can be evaluated. METHODS Eighteen consecutive neonates (mean age 9.2 days, range 1 to 26 days) undergoing an open valvotomy for critical isolated aortic stenosis (the standard treatment for this condition in our unit) between 1984 and 2000 were studied. The mean aortic valve gradient was 79.4 mm Hg. Twelve neonates received prostaglandins and 10 received inotropic agents preoperatively. Follow-up was complete (mean 8.1 years, range 1 month to 15 years). RESULTS There was no operative mortality. At discharge, the mean aortic valve gradient was 37.2 mm Hg, with 6 patients having mild and 2 having moderate aortic regurgitation. Six patients required a reoperation; 3 of these had an aortic valve replacement at 9 to 11 years of age. Kaplan-Meier 5- and 10-year freedoms from any aortic reoperation or reintervention were 85 and 55%, respectively; 5- and 10-year freedoms from aortic valve replacement were 100 and 79%, respectively. A 14-year-old boy died from endocarditis 4 years following an aortic valve replacement in another unit. Kaplan-Meier 10-year survival was 100%. All survivors are in New York Heart Association I class and are leading normal lives. Their mean aortic valve gradient is 34.5 mm Hg, and none has significant aortic regurgitation. CONCLUSIONS Open valvotomy for critical aortic stenosis in neonates carries a low operative risk and provides lengthy freedom from recurrent stenosis or regurgitation. Reoperations are inevitable, but aortic valve replacement can be delayed until the implantation of an adult-sized prosthesis is possible. Late survival is excellent. We consider open surgical valvotomy to be the treatment of choice for critical neonatal aortic stenosis.

Induced hypothermia as salvage treatment for refractory cardiac failure following paediatric cardiac surgery

OBJECTIVE Following corrective cardiac surgery in infants and children for congenital heart disease, a persistent low cardiac output refractory to conventional modes of treatment is associated with a mortality approaching 100%. We advocate the use of whole body hypothermia to reduce tissue oxygen demand and provide a degree of cellular protection against ischaemia allowing time for recovery. We describe our experience. METHODS Between July 1986 and December 1995, 1885 infants and children underwent surgery (operative mortality, 6%), 1302 requiring cardiopulmonary bypass. Fifty-seven patients had a persistent low cardiac output, impaired respiratory function, decreased urine output and acidosis despite maximal intensive care treatment. Cooling to 32-33 degrees C was therefore started using a thermostatically controlled water filled cooling blanket. RESULTS Following cooling, there was a fall in heart rate (P<0.001), a rise in mean arterial pressure (P<0.001) and a fall in mean atrial pressure (P<0.001). Significant (P<0.001) increases in pH and urine output were also recorded. Thirty-one (54%) of the 57 patients treated with cooling survived to leave hospital. No long-term sequelae have been noted in these patients. CONCLUSION Induced hypothermia is a useful salvage treatment, in children following corrective cardiac surgery when all conventional treatment has been tried and failed.

Long‐Term Outcomes Following High Intensity Focused Ultrasound Ablation for Atrial Fibrillation

The aim of this study is to assess the safety and efficacy of the Epicor high intensity focused ultrasound (St. Jude, Inc.®, Minneapolis, MN, USA) system using seven‐day ambulatory electrocardiogram (ECG) monitoring over a two‐year follow‐up period.

National Registry Data and Record Linkage to Inform Postmarket Surveillance of Prosthetic Aortic Valve Models Over 15 Years

Importance Postmarket evidence generation for medical devices is important yet limited for prosthetic aortic valve devices in the United Kingdom. Objective To identify prosthetic aortic valve models that display unexpected patterns of mortality or reintervention using routinely collected national registry data and record linkage. Design, Setting, and Participants This observational study used data from all National Health Service and private hospitals in England and Wales that submit data to the National Adult Cardiac Surgery Audit (NACSA). All patients undergoing first-time elective and urgent aortic valve replacement surgery (with or without coronary artery bypass grafting) with a biological (n = 15 series) or mechanical (n = 10 series) prosthetic valve from 5 primary suppliers, and satisfying prespecified data quality criteria (n = 43 782 biological; n = 11 084 mechanical) between 1998 and 2013 were included. Valves were classified into series of related models. Outcome tracking was performed using multifaceted record linkage. The median follow-up was 4.1 years (maximum, 15.3 years). Cox proportional hazards regression with random effects (frailty models) were used to model valve effects on the outcomes, with and without adjustment for preoperative and intraoperative covariates. Main Outcomes and Measures Time to all-cause mortality or aortic valve reintervention (surgical or transcatheter). There were 13 104 deaths and 723 reinterventions during follow-up. Results Of 79 345 isolated aortic valve replacement procedures with or without coronary artery bypass grafting, 54 866 were analyzed. Biological valve implantation rates increased from 59% in 1998 and 1999 to 86% in 2012 and 2013. Two series of valves associated with significantly increased hazard of death or reintervention were identified (first series: frailty, 1.18; 95% prediction interval [PI], 1.06-1.32 and second series: frailty, 1.19; 95% PI, 1.09-1.31). These results were robust to covariate adjustment and sensitivity analyses. There were 3 prosthetic valves with a significant reduction in hazard (valve 1: frailty, 0.88; 95% PI, 0.80-0.96; valve 2: frailty, 0.88; 95% PI, 0.80-0.96; and valve 3: frailty, 0.88; 95% PI, 0.78-0.98). Conclusions and Relevance Meaningful evidence from the analysis of routinely collected registry data can inform postmarket surveillance of medical devices. Although the findings are associated with a number of caveats, 2 specific biological aortic valve series identified in this study may warrant further investigation.

The use of an esophageal catheter to check the results of left atrial posterior wall isolation in the treatment of atrial fibrillation

Left atrial posterior wall isolation (LAPWI) via catheter, surgical, and hybrid techniques is a promising treatment for persistent atrial fibrillation (PersAF). We investigated whether confirmation of LAPWI can be achieved using an esophageal pacing and recording electrode.

Transapical valve-in-ring mitral valve implantation through the anterior mitral valve leaflet

Transcatheter mitral valve implantation is a relatively novel intervention that replaces the mitral valve of individuals deemed too high-risk or unsuitable for surgery. It is associated with a number of specific risks, including left ventricular outflow tract obstruction. In this report, we present the case of a 75-year-old man who was unable to undergo redo surgical repair and had a number of risk factors for left ventricular outflow tract obstruction. To minimize this risk, we deployed transcatheter mitral valve implantation within the anterior mitral valve leaflet resulting in mild mitral valve regurgitation postoperatively and no left ventricular outflow tract obstruction. Long-term durability of this approach is yet to be determined, but we believe that this intervention adds to the armamentarium of the heart team.

Amaze: a randomized controlled trial of adjunct surgery for atrial fibrillation

Abstract OBJECTIVES Atrial fibrillation (AF) reduces survival and quality of life (QoL). It can be treated at the time of major cardiac surgery using ablation procedures ranging from simple pulmonary vein isolation to a full maze procedure. The aim of this study is to evaluate the impact of adjunct AF surgery as currently performed on sinus rhythm (SR) restoration, survival, QoL and cost-effectiveness. METHODS In a multicentre, Phase III, pragmatic, double-blinded, parallel-armed randomized controlled trial, 352 cardiac surgery patients with >3 months of documented AF were randomized to surgery with or without adjunct maze or similar AF ablation between 2009 and 2014. Primary outcomes were SR restoration at 1 year and quality-adjusted life years at 2 years. Secondary outcomes included SR at 2 years, overall and stroke-free survival, medication, QoL, cost-effectiveness and safety. RESULTS More ablation patients were in SR at 1 year [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.20–3.54; P = 0.009]. At 2 years, the OR increased to 3.24 (95% CI 1.76–5.96). Quality-adjusted life years were similar at 2 years (ablation − control −0.025, P = 0.6319). Significantly fewer ablation patients were anticoagulated from 6 months postoperatively. Stroke rates were 5.7% (ablation) and 9.1% (control) (P = 0.3083). There was no significant difference in stroke-free survival [hazard ratio (HR) = 0.99, 95% CI 0.64–1.53; P = 0.949] nor in serious adverse events, operative or overall survival, cardioversion, pacemaker implantation, New York Heart Association, EQ-5D-3L and SF-36. The mean additional ablation cost per patient was £3533 (95% CI £1321–£5746). Cost-effectiveness was not demonstrated at 2 years. CONCLUSIONS Adjunct AF surgery is safe and increases SR restoration and costs but not survival or QoL up to 2 years. A continued follow-up will provide information on these outcomes in the longer term. Study registration ISRCTN82731440 (project number 07/01/34).

Mitral Valve Repair in Degenerative Mitral Regurgitation: State of the Art

In industrialized countries, the most common etiology of mitral regurgitation (MR) is degenerative mitral valve (MV) disease. The natural history of severe degenerative MR is poor. However, its appropriate and timely correction is associated with a life expectancy similar to that of the normal population. Surgical MV repair is the gold standard treatment. This review will focus on the most recent evidence with a specific emphasis on surgical indications, timing of treatment, contemporary surgical techniques, Heart Teams and Centers of Excellence.