Babu Kunadian

Prospective, randomised, controlled trial to study the effect of intracoronary injection of verapamil and adenosine on coronary blood flow during percutaneous coronary intervention in patients with acute coronary syndromes

Objectives: To study the impact of injection of verapamil and adenosine in the coronary arteries on TIMI (Thrombolysis in Myocardial Infarction) frame count (TFC) after percutaneous coronary intervention (PCI) in patients with an acute coronary syndrome (ACS). Methods: Prospective, randomised, controlled study of the intracoronary administration of normal saline versus verapamil versus adenosine in patients undergoing PCI in the setting of an ACS, even when flow is visually established to be normal or near normal. Patients were randomised to receive verapamil (n  =  49), adenosine (n  =  51) or normal saline (n  =  50) after PCI. Quantitative angiography, TIMI flow grade (TFG), TFC and myocardial blush grade were assessed before PCI, after PCI and after drugs were given. Wall motion index (WMI) was measured at days 1 and 30. Results: 9 patients in the verapamil group developed transient heart block, not seen with adenosine (p ⩽ 0.001). Compared with saline, coronary flow measured by TFC improved significantly and WMI improved slightly but insignificantly in both the verapamil (TFC: p  =  0.02; mean difference in improvement in WMI: 0.09, 95% confidence interval (CI) 0.015 to 0.17, p  =  0.02) and the adenosine groups (TFC: p  =  0.002; mean difference in improvement in WMI: 0.08, 95% CI 0.004 to 0.16, p  =  0.04). The improvements in TFC and WMI did not differ significantly between the verapamil and the adenosine groups (TFC: p  =  0.2; mean difference in improvement in WMI: 0.01, 95% CI −0.055 to 0.08, p  =  0.7, respectively). Conclusion: Administration of verapamil or adenosine significantly improves coronary flow and WMI after PCI in the setting of an ACS. Flow and WMI did not differ significantly between verapamil and adenosine but verapamil was associated with the development of transient heart block.

Meta-analysis of randomized trials comparing anti-embolic devices with standard PCI for improving myocardial reperfusion in patients with acute myocardial infarction

Failure to achieve adequate myocardial reperfusion often occurs during PCI in patients with STEMI. This is in part due to atheromatous and thrombotic distal embolization. Several anti‐embolic devices have been developed to protect against distal embolization during percutaneous coronary interventions (PCI) to improve myocardial reperfusion and enhance event free survival. Evidence from current studies has not shown a consistent benefit, but anti‐embolic devices continue to be used.

Cumulative funnel plots for the early detection of interoperator variation: retrospective database analysis of observed versus predicted results of percutaneous coronary intervention

Objective To use funnel plots and cumulative funnel plots to compare in-hospital outcome data for operators undertaking percutaneous coronary interventions with predicted results derived from a validated risk score to allow for early detection of variation in performance. Design Analysis of prospectively collected data. Setting Tertiary centre NHS hospital in the north east of England. Participants Five cardiologists carrying out percutaneous coronary interventions between January 2003 and December 2006. Main outcome measures In-hospital major adverse cardiovascular and cerebrovascular events (in-hospital death, Q wave myocardial infarction, emergency coronary artery bypass graft surgery, and cerebrovascular accident) analysed against the logistic north west quality improvement programme predicted risk, for each operator. Results are displayed as funnel plots summarising overall performance for each operator and cumulative funnel plots for an individual operator’s performance on a case series basis. Results The funnel plots for 5198 patients undergoing percutaneous coronary interventions showed an average observed rate for major adverse cardiovascular and cerebrovascular events of 1.96% overall. This was below the predicted risk of 2.06% by the logistic north west quality improvement programme risk score. Rates of in-hospital major adverse cardiovascular and cerebrovascular events for all operators were within the 3σ upper control limit of 2.75% and 2σ upper warning limit of 2.49%. Conclusion The overall in-hospital major adverse cardiovascular and cerebrovascular events rates were under the predicted event rate. In-hospital rates after percutaneous coronary intervention procedure can be monitored successfully using funnel and cumulative funnel plots with 3σ control limits to display and publish each operator’s outcomes. The upper warning limit (2σ control limit) could be used for internal monitoring. The main advantage of these charts is their transparency, as they show observed and predicted events separately. By this approach individual operators can monitor their own performance, using the predicted risk for their patients but in a way that is compatible with benchmarking to colleagues, encapsulated by the funnel plot. This methodology is applicable regardless of variations in individual operator case volume and case mix.

Modifiable risk factors remain significant causes of medium term mortality after first time Coronary artery bypass grafting

BackgroundWhilst there is much current data on early outcomes after Coronary artery bypass grafting(CABG), there is relatively little data on medium term outcomes in the current era. The purpose of this study is to present a single surgeon series comprising of all first time CABG patients operated on with the technique of cross clamp fibrillation from Feb-1996 to through to Jan-2003, and to seek risk factors for medium term mortality in these patients.MethodsData was collected from Hospital Episode Statistics and departmental patient administration and tracking systems and cross checked using database techniques. Patient outcomes were searched using the National Health Service strategic tracing service.ResultsMean follow up was 5.3 years(0–9.4 years) and was complete for all patients. 30-day survival was 98.4%, 1-year survival 95% and 8-year survival 79%. Cox-regression analysis revealed that several modifiable pre-operative risk factors remain significant predictors of medium term mortality, including Diabetes(Hazard Ratio(HR) 1.73, 95%CI 1.21–2.45), Chromic obstructive pulmonary disease(HR 2.02, 95%CI 1.09–3.72), Peripheral vascular disease(HR 1.68, 95%CI 1.13–2.5), Body mass index>30(HR 1.54, 95%CI 1.08–2.20) and current smoker at operation(HR 1.67, 95%CI 1.03–2.72). However hypertension(HR 1.31, 95%CI 0.95–1.82) and Hypercholestrolaemia(HR 0.81, 95%CI 0.58–1.13) were not predictive which may reflect adequate post-operative control.ConclusionCoronary artery bypass surgery using cross clamp fibrillation is associated with a very low operative mortality. Medium term survival is also good but risk factors such as smoking at operation, Chronic obstructive pulmonary disease, obesity and diabetes negatively impact this survival and should be aggressively treated in the years post-surgery.

Funnel plots for comparing performance of PCI performing hospitals and cardiologists: demonstration of utility using the New York hospital mortality data.

The New York State Department of Health collects and reports outcome data on the hospitals and cardiologists who perform percutaneous coronary intervention (PCI) to allow them to examine their quality of care. Results are provided in tabular form. However funnel plots are the display method of choice for comparison of institutions and operators, using the principles of statistical process control (SPC). We aimed to demonstrate that funnel plots, which aid a meaningful interpretation of the results, can be derived from the New York PCI dataset.

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.

Is it ever worth contemplating an aortic valve replacement on patients with low gradient severe aortic stenosis but poor left ventricular function with no contractile reserve

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether it is worth performing aortic valve replacement in patients with severe aortic stenosis and poor left ventricular function but no contractile reserve on dobutamine stress testing. Altogether 251 papers were identified using the below mentioned search and all major international guidelines were included. Fourteen presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group, relevant outcomes and weaknesses were tabulated. We conclude that patients with severe aortic stenosis and a contractile reserve of <20% improvement in stroke volume on dobutamine stress testing have a very poor prognosis of only 10-20% at two years. Heart transplant would offer the best chance of survival to those eligible but for those not eligible, a surgical option should not be discounted for selected patients. The American Heart Association guidelines state that prognosis is very poor for either medical or surgical treatment, but the European Society of Cardiology guidelines state that surgery can be performed in these patients but should take into account the clinical condition of the patient. The operative mortality is around 30% and the French Multicentre study on low gradient aortic stenosis has shown that if the patient survives there is likely to be an improvement in symptoms and ejection fraction. Thus, absence of contractile reserve on stress testing does not exclude myocardial recovery after surgery, although it is a strong predictor for operative mortality. It should be noted that surgery has only been reported in very few of these patients to date. B-natriuretic peptide has also been suggested as a further marker of better prognosis in these high-risk patients in one small study.

Impact of catheter sizes and intracoronary glyceryl trinitrate on the TIMI frame count when digital angiograms are acquired at lower frame rates during elective angiography and PCI

The TIMI frame count (TFC) is a useful measure of coronary flow. To be widely applicable, the effect of different catheter sizes and the use of intracoronary glyceryl trinitrate (ICGTN) must be determined when films are acquired at lower acquisition rates (12.5 frames/s, f/s). Methods: We compared 6F versus 5F diagnostic catheters (n = 44), 6F versus 7F diagnostic catheters (n = 45) and 6F diagnostic versus 7F guide catheters (n = 44). In the nitrate angiography group (n = 141), coronary angiography was performed before and after 200 micrograms of ICGTN. In the nitrate percutaneous coronary intervention (PCI) group (n = 48), coronary angiography was performed before and after 200 micrograms of ICGTN after the completion of the elective PCI procedure. Results: The mean difference in the uncorrected TFC using 6F and 5F was 0.02 (95 % CI −0.5, 0.6; P = 0.9); using 6F and 7F diagnostic catheters it was 0.3 (95% CI −0.49, 1.1; p = 0.4); and using 6F diagnostic and 7F guide catheters it was 0.4 (95% CI −2.6, 3.4; P = 0.7) respectively. In the nitrate angiography group, the uncorrected TFC before and after ICGTN was 13.1±6.2 and 15±7.5 (equivalent to 31.4±14.9 and 36±2 at 30 f/s), with a mean difference of 1.9 (95% CI 1.3, 2.5; P = <0.0001). In the nitrate PCI group, the uncorrected TFC before and after ICGTN administration was 9.2±3.7 and 10.3±4.2 (equivalent to 22.6±9.6 and 25.2±11 at 30 f/s) respectively with a mean difference between the two injections of 1.2 (95% CI −0.4, 1.9; P = 0.003). Conclusion: We have demonstrated that the catheter sizes did not significantly affect the TFC when angiography was performed at 12.5f/s. The use of ICGTN significantly increased the TFC in both normal and diseased coronary arteries. This effect was also observed when ICGTN was administered into the culprit vessels after the completion of the elective PCI procedure. This effect must be considered when investigating the impact of specific treatments or drugs on coronary flow.

Rescue angioplasty after failed fibrinolysis foracute myocardial infarction: Predictors of a failed procedure and 1-year mortality

Rescue angioplasty (rPCI) for failed fibrinolysis is associated with a low mortality if successful, but a high mortality if it fails. The latter may reflect a high‐risk group or harm in some patients. Predictors of success or failure of rPCI may aid selection of patients to be treated.

The impact of chronically diseased coronary arteries and stenting on the corrected TIMI frame count in elective coronary angiography and percutaneous coronary intervention procedures.

The impact of chronic coronary obstructions on resting blood flow in stable cardiac patients and the response to percutaneous coronary intervention (PCI) using the TIMI frame count method has not been well documented. We studied the impact of coronary artery stenosis severity on the corrected TIMI frame count (cTFC) in chronically stenosed coronary arteries. We prospectively and quantitatively determined the impact of stenting on the cTFC during elective PCI. Methods: In substudy 1, analysis was performed to obtain the mean cTFC for arteries with <50% stenosis (Group A), 51–75% stenosis (Group B), 76–85% stenosis (Group C1), 86–95% stenosis (Group C2) and 96–99% stenosis (Group C3). In substudy 2, the cTFC and quantitative coronary angiography were performed pre‐ and post‐PCI. Results: In substudy 1, the cTFC increased exponentially beyond a diameter stenosis of 75% (P < 0.01). However there was no significant difference in the cTFC for coronary arteries with <75% stenosis. In substudy 2, the overall pre‐ and poststenting cTFC was 17.1 ± 11.7 and 7.8 ± 2.7 (P < 0.01) and the TFC index [calculated by dividing the mean cTFC for the relevant artery by the mean cTFC for the corresponding coronary artery in a previously derived control group in our laboratory] was 1.6 ± 1 and 0.7 ± 0.2 (P = < 0.01), respectively. Conclusion: We have demonstrated that there was a significant increase in the cTFC when the coronary artery stenosis was more than 75% reflecting significant flow abnormalities at this degree of stenosis in chronically diseased coronary arteries. Following stenting there is a significant improvement in the cTFC, which is better than the cTFC for arteries with normal flow, suggesting early hyperaemia.