Pre-procedural pacing bias among transcatheter aortic valves with higher post-procedure pacing rates: evidence from the UK TAVI Registry.

Rates of permanent pacemaker (PPM) implantation following transcatheter aortic valve implantation (TAVI) are higher than following surgery and are dependent on patient factors and valve type. There is an increasing trend towards pre-emptive PPM insertion in patients with significant conduction disease prior to TAVI. We report results from the British Cardiovascular Intervention Society (BCIS) on pre- and post-procedural PPM implantation in the TAVI population. All centres in the United Kingdom performing TAVI are required to submit data on all TAVI procedures to the National database which are then reported annually. During 2015, there were 2373 TAVI procedures in the UK. 22.4% of TAVI patients had a PPM implanted either pre-procedure (including the distant past), or during the in-hospital procedural episode. Of these, 7.9% were pre-procedure and 14.5% post-procedure. Overall PPM rates were Edwards Sapien (13.5%), Medtronic CoreValve (28.2%) and Boston Lotus (42.1%; p < 0.01). Pre-procedure pacing rates were Edwards Sapien (6.0%), Medtronic CoreValve (9.1%) and Boston Lotus (12.3%; p < 0.01). Pre-procedural pacing rates for the Boston Lotus valve have risen year-on-year from 5.8% (2013) to 8.6% (2014) to 12.3% (2015). The UK TAVI Registry demonstrates a pre-procedural permanent pacing bias amongst patients receiving transcatheter valves with higher post-procedure pacing rates. Pre-emptive permanent pacing is likely to be responsible for this difference.

Determinants of excess mortality following unprotected left main stem percutaneous coronary intervention.

OBJECTIVE: For percutaneous coronary intervention (PCI) to the unprotected left main stem (UPLMS), there are limited long-term outcome data. We evaluated 5-year survival for UPLMS PCI cases taking into account background population mortality. METHODS: A population-based registry of 10 682 cases of chronic stable angina (CSA), non-ST-segment elevation acute coronary syndrome (NSTEACS), ST-segment elevation myocardial infarction with (STEMI+CS) and without cardiogenic shock (STEMI-CS) who received UPLMS PCI from 2005 to 2014 were matched by age, sex, year of procedure and country to death data for the UK populace of 56.6 million people. Relative survival and excess mortality were estimated. RESULTS: Over 26 105 person-years follow-up, crude 5-year relative survival was 93.8% for CSA, 73.1% for NSTEACS, 77.5% for STEMI-CS and 28.5% for STEMI+CS. The strongest predictor of excess mortality among CSA was renal failure (EMRR 6.73, 95% CI 4.06 to 11.15), and for NSTEACS and STEMI-CS was preprocedural ventilation (6.25, 5.05 to 7.75 and 6.92, 4.25 to 11.26, respectively). For STEMI+CS, the strongest predictor of excess mortality was preprocedural thrombolysis in myocardial infarction (TIMI) 0 flow (2.78, 1.87 to 4.13), whereas multivessel PCI was associated with improved survival (0.74, 0.61 to 0.90). CONCLUSIONS: Long-term survival following UPLMS PCI for CSA was high, approached that of the background populace and was significantly predicted by co-morbidity. For NSTEACS and STEMI-CS, the requirement for preprocedural ventilation was the strongest determinant of excess mortality. By contrast, among STEMI+CS, in whom survival was poor, the strongest determinant was preprocedural TIMI flow. Future cardiovascular cohort studies of long-term mortality should consider the impact of non-cardiovascular deaths.

Patient and hospital determinants of primary percutaneous coronary intervention in England, 2003-2013.

OBJECTIVE: Primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) is insufficiently implemented in many countries. We investigated patient and hospital characteristics associated with PPCI utilisation. METHODS: Whole country registry data (MINAP, Myocardial Ischaemia National Audit Project) comprising PPCI-capable National Health Service trusts in England (84 hospital trusts; 92 350 hospitalisations; 90 489 patients), 2003-2013. Multilevel Poisson regression modelled the relationship between incidence rate ratios (IRR) of PPCI and patient and trust-level factors. RESULTS: Overall, standardised rates of PPCI increased from 0.01% to 86.3% (2003-2013). While, on average, there was a yearly increase in PPCI utilisation of 30% (adjusted IRR 1.30, 95% CI 1.23 to 1.36), it varied substantially between trusts. PPCI rates were lower for patients with previous myocardial infarction (0.95, 0.93 to 0.98), heart failure (0.86, 0.81 to 0.92), angina (0.96, 0.94 to 0.98), diabetes (0.97, 0.95 to 0.99), chronic renal failure (0.89, 0.85 to 0.90), cerebrovascular disease (0.96, 0.93 to 0.99), age >80 years (0.87, 0.85 to 0.90), and travel distances >30 km (0.95, 0.93 to 0.98). PPCI rates were higher for patients with previous percutaneous coronary intervention (1.09, 1.05 to 1.12) and among trusts with >5 interventional cardiologists (1.30, 1.25 to 1.34), more visiting interventional cardiologists (1-5: 1.31, 1.26 to 1.36; ≥6: 1.42, 1.35 to 1.49), and a 24 h, 7-days-a-week PPCI service (2.69, 2.58 to 2.81). Half of the unexplained variation in PPCI rates was due to between-trust differences. CONCLUSIONS: Following an 8 year implementation phase, PPCI utilisation rates stabilised at 85%. However, older and sicker patients were less likely to receive PPCI and there remained between-trust variation in PPCI rates not attributable to differences in staffing levels. Compliance with clinical pathways for STEMI is needed to ensure more equitable quality of care.

Response of the pulmonary circulation to acetylcholine, calcitonin gene-related peptide, substance P and oral nicardipine in patients with primary pulmonary hypertension.

Endothelium-dependent vasodilation of the pulmonary vascular bed was investigated in five patients with primary pulmonary hypertension. Three endothelium-dependent vasodilators (acetylcholine, calcitonin gene-related peptide and substance P [in two patients]) were infused sequentially into the right atrium, followed by nicardipine given orally during full hemodynamic monitoring. Acetylcholine, calcitonin gene-related peptide and substance P had no effect on pulmonary artery pressure, total pulmonary vascular resistance or cardiac output, although calcitonin gene-related peptide significantly decreased systemic arterial systolic pressure from 132 +/- 34 to 113 +/- 33 mm Hg. In contrast, oral nicardipine decreased total pulmonary vascular resistance from 23 +/- 12 to 13 +/- 8 U, with a concomitant increase in cardiac output from 3.1 +/- 1 to 4.7 +/- 2 liters.min-1 and decrease in systemic vascular resistance from 30 +/- 9 to 13 +/- 4 U. Thus, despite the presence of a reversible component in these five patients with primary pulmonary hypertension, pulmonary vascular resistance did not decrease in response to the infused endothelium-dependent vasodilator agents, indicating that endothelium-dependent vasodilation is impaired in these patients.

Measurement accuracy of cardiac output in humans: indicator-dilution technique versus geometric analysis by ultrafast computed tomography.

OBJECTIVES: The aim of this study was to evaluate measurement accuracy of cardiac output in humans by comparing the indicator-dilution technique with geometric analysis by ultrafast computed tomography. BACKGROUND: Ultrafast computed tomography can be used to measure cardiac output by two methods. First, by scanning to obtain end-systolic and end-diastolic short-axis images of the ventricular cavities at sequential tomographic levels, the stroke volume and therefore the cardiac output can be calculated. Second, indicator-dilution theory (the Stewart-Hamilton equation) can be applied to measurements of the concentration of radiographic contrast in the blood pool after a bolus injection. The latter method has not been validated in humans. METHODS: The accuracy of the geometric method itself was first established by comparing left and right ventricular stroke volumes in 29 patients without valvular regurgitation or an intracardiac shunt, whose left and right ventricular stroke volumes should have been identical (group A). In a subset of 17 patients, the geometric method was compared with the indicator-dilution method (group B). RESULTS: Geometric analysis showed that the mean difference between left and right ventricular stroke volume was 1.8 +/- 7.3 ml, with a percentage SD of the differences of 9.3% (r = 0.9). Comparison wih indicator dilution-calculated cardiac output showed a mean difference of 0.079 +/- 1.22 liters/min, with a percent SD of the differences of 23.7% (r = 0.6). There was no improvement in this comparison with individual calibration of the scanner for each patient. CONCLUSIONS: The disparity found between data obtained with the geometric and indicator-dilution methods may be a result of the hemodynamic effects of contrast medium or it may suggest the possibility that some assumptions of indicator-dilution theory are not valid.

Skeletal muscle blood flow in heart failure measured by ultrafast computed tomography: validation by comparison with plethysmography.

OBJECTIVES: Abnormalities of skeletal muscle perfusion and metabolism may be important in the symptomatic limitation of patients with chronic heart failure. A method for assessing both skeletal muscle blood flow and mass would be useful in clinical practice and research. Ultrafast computed tomography has the potential to make these measurements. The aim was to determine the accuracy with which skeletal muscle blood flow could be measured by ultrafast computed tomography in patients with chronic heart failure. METHODS: Leg blood flow measured by venous occlusion plethysmography was compared with skeletal muscle blood flow by ultrafast computed tomography. Fourteen patients with chronic heart failure (aged 51 to 76 years) were investigated. Plethysmography and ultrafast computed tomography measurements were performed at rest and during hyperaemic flow induced by symptom limited bicycle exercise followed by five minutes of leg ischaemia. The ultrafast computed tomography measurements were made by analysing the opacification of the blood pool and of the muscle after an intravenous bolus of non-ionic radio-opaque contrast. RESULTS: Flows assessed by plethysmography ranged from 1.5 to 38.1 ml x 100 ml-1 x min-1. The slope of the line relating the two methods was 1.1 (95% confidence interval 0.91 to 1.31), and the mean (95% limits of agreement) of the differences between the two methods was 2.5(10.6) ml x 100 ml-1 x min-1. CONCLUSIONS: Ultrafast computed tomography is a useful tool in the measurement of both skeletal muscle mass and perfusion in humans.

Automated cardiopulmonary resuscitation using a load-distributing band external cardiac support device for in-hospital cardiac arrest: a single centre experience of AutoPulse-CPR.

BACKGROUND: Poor quality cardiopulmonary resuscitation (CPR) predicts adverse outcome. During invasive cardiac procedures automated-CPR (A-CPR) may help maintain effective resuscitation. The use of A-CPR following in-hospital cardiac arrest (IHCA) remains poorly described. AIMS & METHODS: Firstly, we aimed to assess the efficiency of healthcare staff using A-CPR in a cardiac arrest scenario at baseline, following re-training and over time (Scenario-based training). Secondly, we studied our clinical experience of A-CPR at our institution over a 2-year period, with particular emphasis on the details of invasive cardiac procedures performed, problems encountered, resuscitation rates and in-hospital outcome (AutoPulse-CPR Registry). RESULTS: Scenario-based training: Forty healthcare professionals were assessed. At baseline, time-to-position device was slow (mean 59 (±24) s (range 15-96s)), with the majority (57%) unable to mode-switch. Following re-training time-to-position reduced (28 (±9) s, p<0.01 vs baseline) with 95% able to mode-switch. This improvement was maintained over time. AutoPulse-CPR Registry: 285 patients suffered IHCA, 25 received A-CPR. Survival to hospital discharge following conventional CPR was 28/260 (11%) and 7/25 (28%) following A-CPR. A-CPR supported invasive procedures in 9 patients, 2 of whom had A-CPR dependant circulation during transfer to the catheter lab. CONCLUSION: A-CPR may provide excellent haemodynamic support and facilitate simultaneous invasive cardiac procedures. A significant learning curve exists when integrating A-CPR into clinical practice. Further studies are required to better define the role and effectiveness of A-CPR following IHCA.

Transient ST-segment changes associated with mitral valvuloplasty using the Inoue balloon.

We describe unexplained transient inferior ST-segment elevation on the electrocardiogram during Inoue mitral valvuloplasty in 8 patients from a series of 108. Electrocardiographic changes were associated with chest pain in 7 patients, and although the clinical features were suggestive of myocardial ischemia, no cause for this could be found.

Determinants of transplant-related coronary calcium detected by ultrafast computed tomography scanning.

Coronary calcium detected by ultrafast computed tomography (CT) has been shown to be a marker of coronary artery disease in heart transplant recipients. The objective of this study was to examine the possible determinants of coronary calcium after heart transplantation. Over a 15-month period, 102 consecutive cardiac transplant recipients (mean age 53 years, 88 men) underwent ultrafast CT scanning of the heart, in addition to coronary angiography, to determine coronary calcium score on their annual follow-up (a median of 4.6 years [range 63 days to 9.1 years] after transplant). The following data were also recorded: the recipient's sex and date of birth, date of transplantation, date of ultrafast computed tomography and coronary angiography; recipient pretransplant diagnosis, history of diabetes mellitus and systemic hypertension, fasting lipid profile, immunosuppression, number of rejection episodes, and donor organ ischemic time. Forty six patients (45.1%) had total calcium scores >0 and 41 (40.2%) had at least 1 major coronary with angiographic narrowing >24%. On univariate analysis, coronary calcium was significantly associated with dyslipoproteinemia, total cholesterol was >6.0 mmol/L (240 mg/dl), triglycerides were >3.0 mmol/L (265 mg/dl), and lipoprotein(a) >30 mg/ dl; > or =25% angiographic disease was significantly associated with coronary calcium and dyslipoproteinemia. Logistic regression revealed that dyslipoproteinemia, systemic hypertension, and donor ischemic time were significant predictors of coronary calcium in transplanted hearts. We conclude that the prevalence of coronary calcium in heart transplant recipients is high and is related to recipient dyslipoproteinemia, systemic hypertension, and donor organ ischemic time.

Radial versus femoral approach for diagnostic coronary angiography in stable angina pectoris.

We compared coronary angiography of the radial artery using 6Fr catheters in 116 patients with that of the femoral artery in 100 case controls. We showed that transradial coronary angiography offers a useful alternative to the femoral route and can be performed without resorting to 5Fr catheters.

Comparison of radial versus brachial approaches for diagnostic coronary angiography when the femoral approach is contraindicated.

One hundred patients with contraindications to the femoral approach were randomized to undergo diagnostic coronary angiography via percutaneous radial puncture or brachial artery cutdown. Procedure duration, fluoroscopy time, and total radiation dose were significantly less via the radial route, whereas procedural success, complication rates, and pain scores were comparable; we conclude that the radial technique should be the arm approach of choice for new trainees, although there will be occasions when radial access fails and a brachial approach is required.

Changing from intensive anticoagulation to treatment with aspirin alone for coronary stents: the experience of one centre in the United Kingdom.

OBJECTIVE: To investigate whether an elective change in the anticoagulation protocol for patients with coronary stents affected clinical outcomes and length of hospital stay. DESIGN: Retrospective observational study of a consecutive series of patients treated with coronary stents over an 18 month period from April 1994 to October 1995. BACKGROUND: Intensive anticoagulation regimens are used in many UK centres to reduce the risk of coronary stent thrombosis. Recent data have called into question the necessity for full anticoagulation and favourable results have been reported with antiplatelet agents alone. The results from a tertiary referral centre were investigated during a period where an elective change in policy was made: an initial 70 patients were treated intensively with intravenous heparin and with warfarin and aspirin; subsequently 94 were treated with aspirin and deployment of a high pressure balloon only. METHODS: Review of case notes, angiograms, and a database of intervention procedures and telephone interview. Classic epidemiological techniques, as well as linear regression and logistic regression, were used to model the outcomes of major procedural complications and length of hospital stay. PATIENTS: 164 patients treated with 196 coronary stents. RESULTS: There were 22 (13.4%) major complications (coronary bypass grafting 11, subacute thrombosis 6, tamponade 2, myocardial infarction 1, death 2). With logistic regression, the risk of major complication was shown not to be affected by anticoagulation (relative risk (RR) 1.03; P = 0.97). Significant determinants of risk included acute vessel closure as an indication for stenting (RR = 80.6; P < 0.001) and sex (male: female RR = 0.19; P = 0.02). The median length of stay (LOS) was 5 days (1-45). Use of a linear regression model showed that anticoagulation added 4.5 days and a major complication added a further 4.5 days to a baseline length of stay of 3.2 days (R2 = 0.32; P < 0.001). CONCLUSION: This is a report of coronary stenting as part of usual clinical practice in one British tertiary referral centre. In this experience, treatment with aspirin alone is probably as safe as intensive anticoagulation, and has the benefit of reducing length of stay by more than 50% to 3.2 days in an uncomplicated case.

Late complications following permanent pacemaker implantation or elective unit replacement.

OBJECTIVE: To determine the rate of late complications following first implantation or elective unit replacement of a permanent pacemaker system. DESIGN: Analysis of pacemaker data and complications prospectively acquired on a computerised database. Complications were studied over an 11 year period from January 1984 to December 1994. SETTING: Tertiary referral cardiothoracic centre. PATIENTS: Records of 2621 patients were analysed retrospectively. MAIN OUTCOME MEASURES: Complications requiring repeat procedures occurring more than six weeks after pacemaker implantation or elective unit replacement. RESULTS: The overall rate of late complications was significantly lower after first implantation of a permanent pacemaker (34 cases, complication rate 1.4%, 95% confidence interval 0.9% to 1.9%) than after elective unit replacement (16 cases, complication rate 6.5% (3.3% to 9.7%). There were 20 cases of erosion, 18 infections, five electrode problems, and seven miscellaneous problems. Complications were more common with inexperienced operators (18.9% (6.0% to 31.8%)) than with experienced operators (0.9% (0.3% to 1.5%). CONCLUSIONS: The incidence of late complications following pacemaker implantation is low and compares favourably with early complication rates. The majority are caused by erosion and infection. Patients who have undergone elective unit replacement are at particular risk.

Balloon mitral valvuloplasty: comparison of haemodynamic and echocardiographic assessment of mitral stenosis at different heart rates in the catheterisation laboratory.

AIMS: To compare echo-Doppler, Gorlin equation and haemodynamic methods of measuring mitral valve stenosis during right ventricular pacing-induced tachycardia before and after Inoue balloon mitral valvuloplasty to determine which method gave the most consistent results. METHODS AND RESULTS: Measurements were made before and after valvuloplasty at: baseline heart rates, paced at 115 and then 145 beats/min. Mitral valve area by echo-Doppler was 1.1(+/-0.1) cm2 (mean +/- S.E.) before and 1.8(+/-0.2) cm2 after valvuloplasty; and by Gorlin equation: 0.9(+/-0.1) cm2 before and 1.5(+/-0.1) cm2 after. Echo-Doppler measurements were heart rate dependent but those by Gorlin measurements were not. At baseline, cardiac index was 2.08(+/-0.2) l min(-1), left atrial pressure 23.3(+/-7.9) mm Hg and mean mitral diastolic gradient 16.9(+/-9.9) mm Hg. After valvuloplasty, cardiac index was 2.31(+/-0.1) l min(-1), left atrial pressure fell to 19.2(+/-5.6) mm Hg and mean diastolic gradient was reduced to 8.5(+/-1.8) mm Hg. CONCLUSIONS: The Gorlin mitral valve area appeared to be the most heart rate independent indicator of success following valvuloplasty.

Coronary angiography from the radial artery--experience, complications and limitations.

AIMS: to assess the outcomes, complications and limitations of coronary angiography performed via percutaneous radial artery puncture. METHODS AND RESULTS: two hundred and fifty patients underwent diagnostic coronary angiography from the radial artery, 182 (72.8%) of whom had contraindications to the femoral approach, for example due to peripheral vascular disease (n=85), therapeutic anticoagulation (29), or failed femoral approach (17). Procedural success in this high-risk population was achieved in 231 patients (92.4%). Principle reasons for failure were unsuccessful radial access (5) and arterial spasm (5). Procedure duration (SD) for an operator's first 20 cases compared with cases thereafter (min) was 47.7 (16.7) vs. 41.5 (14.6), P=0.0004; fluoroscopy time (min) 9.7 (7.1) vs. 6.6 (5.1), P=0.0001 and procedural success 89.6% vs. 94.1%, P=ns. Complications included two deaths associated temporally with catheterisation, three cases of arterial dissection without ischaemic sequelae and one transient ischaemic attack. CONCLUSIONS: coronary angiography can be performed successfully from the radial artery, but this approach has limitations, which include the need to demonstrate dual palmar vascular supply, the prolonged learning phase, the procedural failure rate, patient discomfort and a demonstrable incidence of vascular and haemodynamic complications. We believe that radial coronary angiography should only be undertaken when there is a contraindication to the femoral approach.