A Turley

Effect of short-term exercise training on aerobic fitness in patients with abdominal aortic aneurysms: a pilot study

BACKGROUND Patients with abdominal aortic aneurysms (AAA) represent a high-risk surgical group. Despite medical optimization and radiological stenting interventions, mortality remains high and it is difficult to improve fitness. The aim of this pilot study was to evaluate the effect of a 6 week, supervised exercise programme (30 min continuous moderate intensity cycle ergometry, twice weekly) on anaerobic threshold (AT) in subjects with AAA. METHODS Thirty participants with an AAA under surveillance were randomized to either the supervised exercise intervention (n=20) or a usual care control group (n=10). AT was measured using cardiopulmonary exercise testing, at baseline (AT1), week 5 (AT2), and week 7 (AT3). The change in AT (AT3-AT1) between the groups was compared using a mixed model ancova, providing the mean effect together with the standard deviation (sd) for individual patient responses to the intervention. The minimum clinically important difference (MCID) was defined as an improvement in AT of 2 ml O(2) kg(-1) min(-1). RESULTS Of the 30 participants recruited, 17 of 20 (exercise) and eight of 10 (control) completed the study. The AT in the intervention group increased by 10% (equivalent to 1.1 ml O(2) kg(-1) min(-1)) compared with the control (90% confidence interval 4-16%; P=0.007). The sd for the individual patient responses to the intervention was 8%. The estimated number needed to treat (NNT) for benefit was 5 patients. CONCLUSIONS The small mean benefit was lower than the MCID. However, the marked variability in the individual patient responses revealed that a proportion of patients did benefit clinically, with an estimated NNT of 5.

In patients undergoing aortic valve replacement, what factors predict the requirement for permanent pacemaker implantation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question was to determine what preoperative, perioperative and postoperative factors influence the requirement for permanent pacemaker (PPM) implantation postisolated aortic valve replacement (AVR). Transcatheter aortic valve intervention was not included in this analysis. Using the reported search method outlined below, 705 papers were found. No randomised controlled trials, meta-analyses or registries were identified. Seven single-centre retrospective observational studies represent the best evidence on the subject. The author, journal, date and country of publication, level of evidence, patient group studied, study type, outcomes and results were tabulated. The incidence of PPM implantation following AVR varied from 3.0% to 11.8% (mean 7.0%, median 7.2%). Current best available evidence suggests that baseline evidence of conducting system disease - first degree atrioventricular block (AVB), left anterior hemiblock, right bundle branch block (RBBB) or left bundle branch block (LBBB) is the most powerful independent predictor of PPM requirement following AVR. Other important predictors are surgery for aortic regurgitation, preoperative myocardial infarction and longer perioperative cardiopulmonary bypass time. No consistent postoperative factors were identified. The mean time to PPM implant postAVR ranged from 6 to 13 days in the four studies that reported it. Current European Society of Cardiology guidelines recommend a period of seven days of persistent AVB postsurgery prior to PPM implantation.

Postoperative permanent pacemaker implantation in patients undergoing trans-catheter aortic valve implantation: what is the incidence and are there any predicting factors?

A best evidence topic was written according to a structured protocol. The issue was to determine the incidence and predictors of postoperative permanent pacemaker (PPM) implantation in patients undergoing trans-catheter aortic valve implantation (TAVI) for symptomatic calcific aortic stenosis and to compare this to the known risks of this complication following surgical aortic valve replacement (AVR). Using the reported search method 3071 articles were identified, of which 94 were relevant to the procedure of TAVI and 14 were deemed to represent the best evidence. All 14 studies, including both multi-centre registries and single-centre retrospective case series containing ≥30 patients, reported incidence of postoperative PPM implantation. Five of these studies also assessed predictors of the need for postoperative PPM implantation. The author, journal, date and country of publication, study type, level of evidence, patient group, outcomes and results were tabulated for these studies. We conclude that the current best available evidence suggests that the mean incidence of PPM implantation following TAVI is 14.2% (range 0-34%, median 9.7%), although this appears higher with the CoreValve prosthesis (five studies, mean 20.8%, range 9.3-30.0%) than with the Edwards-Sapien prosthesis (six studies, mean 5.4%, range 0-10.1%). The mean incidences of PPM implantation overall and when using the CoreValve prosthesis are higher than the mean incidence of 7.0% (range 3-11.8%, median 7.2%) following conventional AVR and may be explained by distinct differences between the patient groups involved and the procedure performed. Indications for PPM implantation appear to occur early in the postoperative period following TAVI and there is little evidence of recovery following atrioventricular block (AVB). New onset persistent left bundle branch block is common following TAVI but the significance and follow-up required is unclear. Independent predictors of PPM requirement following TAVI include use of the CoreValve prosthesis and evidence of conduction system dysfunction, either pre-existing right bundle branch block or AVB at the time of TAVI. All patients should be made aware of the high risk of PPM implantation with TAVI.

Reliability of the anaerobic threshold in cardiopulmonary exercise testing of patients with abdominal aortic aneurysms.

Anaerobic threshold (AT), determined by cardiopulmonary exercise testing (CPET), is a well‐documented measure of pre‐operative fitness, although its reliability in patient populations is uncertain. Our aim was to assess the reliability of AT measurement in patients with abdominal aortic aneurysms. Eighteen patients were recruited. CPET was performed four times over a 6‐week period. We examined shifts in the mean AT to evaluate systematic bias with random measurement error assessed using typical within‐patient error and intraclass correlation coefficient (ICC, 3,1) statistics. There was no significant or clinically substantial change in mean AT across the tests (p = 0.68). The typical within‐patient error expressed as a percentage coefficient of variation was 10% (95% CI, 8–13%), with an ICC of 0.74 (95% CI, 0.55–0.89). We consider the reliability of the AT to be acceptable, supporting its clinical validity and utility as an objective marker of pre‐operative fitness in this population.

Does cardiac resynchronisation therapy improve survival and quality of life in patients with end-stage heart failure?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether bi-ventricular pacing, also referred to as cardiac resynchronisation therapy (CRT), improves survival and quality of life in patients with severe (NYHA III/IV) symptomatic heart failure. Cardiac pacing can be achieved by stimulation of the right ventricle, left ventricle (LV) or by bi-ventricular pacing. This best evidence topic considers only bi-ventricular pacing. This involves placement of pacing leads in the right ventricle, epicardially on the LV with a lead typically placed in a branch of the coronary sinus and, unless the patient is in permanent atrial fibrillation, in the right atrium. Bi-ventricular pacing allows the optimisation of atrio-ventricular timing and resynchronisation of septal and postero-lateral left ventricular contraction. Symptomatic heart failure has a high morbidity and a poor prognosis. Patients with dyspnoea at rest or on minimal exertion (NYHA III/IV) are at high risk of death due to progressive heart failure, while those with less severe symptoms are more likely to experience sudden cardiac death. Up to 50% of patients with NYHA class III/IV symptoms have a prolonged QRS duration (>120 ms) on 12-lead ECG (usually in a LBBB pattern). This intra-ventricular conduction delay is a surrogate marker of mechanical dyssynchrony (an uncoordinated regional contraction-relaxation pattern) and is associated with reduced cardiac output and increased mortality. Bi-ventricular pacing can reduce the delay in activation of the LV free wall found in many patients with LV systolic dysfunction, thereby improving mechanical synchrony and cardiac output. It may also reduce pre-systolic mitral regurgitation. Three hundred and fifty-six papers were identified using the search method outlined, nine randomised controlled trials and a meta-analysis in addition to published guidelines presented the best evidence to answer the clinical question. Current best available evidence suggests that in patients with left ventricular systolic dysfunction (LVEF </=35%), prolonged QRS duration (QRS >or=120 ms), and NYHA class III or IV symptoms despite optimal pharmacological therapy, bi-ventricular pacing significantly reduces the number of hospitalisations from heart failure, improves functional status (NYHA class, peak oxygen uptake and exercise tolerance) and improves health related quality of life. The CARE-HF study also demonstrated a reduction in mortality from progressive heart failure and all-cause mortality.

Secondary prevention following coronary artery bypass grafting has improved but remains sub-optimal: the need for targeted follow-up

A focused review of secondary preventive medication following revascularisation provides an opportunity to ensure optimal use of these agents. A retrospective analysis of our in-house cardiothoracic surgical database was performed to identify patients undergoing non-emergency, elective surgical revascularisation discharged on four secondary preventive medications: aspirin; beta-blockers; ACE-inhibitors and statins. Of 2749 patients studied, 2302 underwent isolated coronary artery bypass grafting (CABG), mean age 65.5 years (S.D. 9.15). Overall, 2536 (92%) patients were prescribed aspirin. Beta-blockers were prescribed in 2171 (79%) patients overall, in 1096/1360 (81%) of patients with a history of myocardial infarction and in 465/619 (75%) of patients with left ventricular systolic dysfunction (LVSD). Overall, 1518 (55%) patients were prescribed an ACE-inhibitor and 179 (6.5%) an angiotensin receptor blocker (ARB); one of these agents was prescribed in 446/619 (72%) patients with LVSD and 915/1360 (67%) patients with a history of previous myocardial infarction. Overall, 2518 (92%) patients were prescribed a statin. Secondary preventive therapies are prescribed more commonly on discharge after CABG than in previous studies, but there is a continuing under-utilisation of ACE-inhibitors. To maximise the potential benefits of these agents, further study is required to understand why they are not prescribed.

External Validation of Established Risk Adjustment Models for Procedural Complications after Percutaneous Coronary Intervention

Background: Workable risk models for patients undergoing percutaneous coronary intervention (PCI) are needed urgently. Objective: To validate two proposed risk adjustment models (Mayo Clinic Risk Score (MC), USA and North West Quality Improvement Programme (NWQIP), UK models) for in-hospital PCI complications on an independent dataset of relatively high risk patients undergoing PCI. Setting: Tertiary centre in northern England. Methods: Between September 2002 and August 2006, 5034 consecutive PCI procedures (validation set) were performed on a patient group characterised by a high incidence of acute myocardial infarction (MI; 16.1%) and cardiogenic shock (1.7%). Two external models—the NWQIP model and the MC model—were externally validated. Main outcome measure: Major adverse cardiovascular and cerebrovascular events: in-hospital mortality, Q-wave MI, emergency coronary artery bypass grafting and cerebrovascular accidents. Results: An overall in-hospital complication rate of 2% was observed. Multivariate regression analysis identified risk factors for in-hospital complications that were similar to the risk factors identified by the two external models. When fitted to the dataset, both external models had an area under the receiver operating characteristic curve ⩾0.85 (c index (95% CI), NWQIP 0.86 (0.82 to 0.9); MC 0.87(0.84 to 0.9)), indicating overall excellent model discrimination and calibration (Hosmer–Lemeshow test, p>0.05). The NWQIP model was accurate in predicting in-hospital complications in different patient subgroups. Conclusions: Both models were externally validated. Both predictive models yield comparable results that provide excellent model discrimination and calibration when applied to patient groups in a different geographic population other than that in which the original model was developed.

Strain rate imaging pre- and post-percutaneous coronary intervention: a potential role in the objective detection of ischaemia in exercise stress echocardiography

AIMS To determine the feasibility of strain rate imaging (SRI) in the objective detection of exercise-induced ischaemia. METHODS AND RESULTS Sixteen patients undergoing elective percutaneous coronary intervention (PCI) underwent treadmill exercise stress echocardiography (ESE) pre- and post-PCI. Measurement of systolic SRI parameters was attempted in all myocardial segments at baseline, peak stress, and in recovery. Segments were divided into those supplied by target (Group 1) and non-target vessels (Group 2). Percutaneous coronary intervention was successful in all patients. In Group 1, there was no significant difference in post-systolic strain rate (SRps) at baseline or at peak stress but there was significantly greater SRps pre-PCI compared with post-PCI at 30 min into recovery (-0.37 +/- 0.53 vs. -0.07 +/- 0.44 s(-1), P = 0.004). There were similar findings with the SRps index [ratio of SRps:peak systolic strain rate (SRsys)]. Group 2 segments did not demonstrate any significant differences in SRI parameters pre- and post-PCI. At peak exercise pre-PCI, Group 1 segments had significantly delayed time to SRsys compared with Group 2 (0.12 +/- 0.05 vs. 0.09 +/- 0.05 s, P = 0.013), a difference that was abolished post-PCI. CONCLUSION This suggests a potential role for SRI in the objective detection of exercise-induced ischaemia by echocardiography at peak stress and during recovery at the time of improved image quality.

Takotsubo cardiomyopathy in two female patients: two case reports.

BackgroundTako-tsubo cardiomyopathy (idiopathic apical ballooning syndrome or ampulla cardiomyopathy) has recently been described. First recognised in Japanese patients, tako-tsubo refers to the end-systolic appearance of the left ventricle on ventriculography and its resemblance to the round bottomed, narrow necked Japanese fishing pots used to trap octopusCase presentationWe present two cases of female caucasian patients aged 40 and 63 years respectively admitted following severe stressful events who met the diagnostic criteria of tako-tsubo cardiomyopathy, namely acute chest pain, transient akinesis or dyskinesia of the left ventricle, new dynamic electrocardiogram changes and no significant epicardial coronary artery disease in the absence of recent head trauma, intracranial bleeding, phaeochromocytoma, myocarditis and hypertrophic cardiomyopathy. Both had elevated cardiac biomarkers. Characteristically the condition is transient and the abnormal akinesia/dyskinesia of the left ventricle has been observed to normalise within 1-month as in our patients who made full recoveries.ConclusionPatients with tako-tsubo cardiomyopathy present with features consistent with an acute coronary syndrome and as such the syndrome is probably under-diagnosed. It may be with the introduction of primary percutaneous coronary intervention more cases are identified, sparing patients the risks of unnecessary thrombolytic therapy. Tako-tsubo cardiomyopathy should be considered in all patients presenting with acute onset chest pain and elevated cardiac biomarkers.

Video-assisted thoracoscopic left ventricular pacing in patients with and without previous sternotomy.

BACKGROUND Left ventricular epicardial lead placement via video-assisted thoracoscopy (VAT) is a recognized surgical technique to achieve cardiac resynchronization therapy (CRT) when conventional lead placement has failed. Its role in patients with previous sternotomy is uncertain. We describe our experience in a cohort of patients including those with previous sternotomy. METHODS This was a retrospective review of consecutive patients undergoing VAT lead implantation for CRT in a single center between 2004 and 2011. All patients fulfilled conventional criteria for CRT and were followed up at 4 to 6 weeks and then at 3-month intervals. Clinical and pacing parameters were compared at baseline and at the latest review. RESULTS Thirty-two patients (27 men; mean age, 67 ± 9 years) underwent VAT left ventricular lead implantation. Mean follow-up duration was 704 ± 450 days. Ten patients (31%) had undergone previous sternotomy. Thoracoscopic lead implantation was successful in 31 patients (97%): 1 patient with two previous sternotomies required conversion to open thoracotomy due to bleeding with multiple adhesions. Satisfactory implantation pacing thresholds of 2 volts or less at 0.5 ms were achieved in all patients. Despite a longer operative time in those with previous sternotomy, all clinical and pacing outcomes, including complications, clinical response to CRT, and long-term pacing variables were similar between the groups. CONCLUSIONS VAT left ventricular lead placement appears safe and effective in selected patients with previous sternotomy, including coronary artery bypass operations, with postoperative outcomes comparable with those patients without previous sternotomy.