Albert E. Alahmar

Cardiopulmonary exercise testing and its application

Cardiopulmonary exercise testing CPET has become an important clinical tool to evaluate exercise capacity and predict outcome in patients with heart failure and other cardiac conditions. It provides assessment of the integrative exercise responses involving the pulmonary, cardiovascular and skeletal muscle systems, which are not adequately reflected through the measurement of individual organ system function. CPET is being used increasingly in a wide spectrum of clinical applications for evaluation of undiagnosed exercise intolerance and for objective determination of functional capacity and impairment. This review focuses on the exercise physiology and physiological basis for functional exercise testing and discusses the methodology, indications, contraindications and interpretation of CPET in normal people and in patients with heart failure.

Lesion Complexity and Angiographic Outcomes in Radial Access Percutaneous Coronary Intervention

BACKGROUND Percutaneous coronary intervention (PCI) is increasingly performed from the radial arterial (RA) access site. Few studies have examined the interaction between a default radial approach, lesion complexity, and angiographic outcome. This study investigates lesion complexity, arterial access route, and angiographic outcome in routine clinical practice by default radial operators. METHODS All cases of PCI over a 12-month period (Jan 2005 to Jan 2006) at our regional cardiac center were prospectively entered into a database detailing arterial access route, target vessel and lesion characteristics, and lesion-specific angiographic outcome. Angiographic success was defined as residual stenosis <50% for balloon angioplasty alone or <20% for a stented lesion in the presence of TIMI 3 flow in the target vessel. All procedures carried out by default radial operators were selected for further retrospective analysis. Reasons for not completing a case via the radial route were recorded. Radial and femoral cases by default radial operators were evaluated on grounds of lesion complexity and angiographic outcome for each treated lesion. RESULTS RA was the intended route in 91.5% of 1,324 procedures (91.5% of 2,239 lesions), and the final route in 90.1% of procedures (90.2% of lesions). There were 19 crossover procedures (30 lesions), all from radial to femoral access (FA). Crossovers were due to failed radial artery cannulation or sheath placement (9 procedures), inability to advance the guide catheter into the aortic root (7 procedures), and other guide catheter handling or support issues (3 procedures). Counting crossovers as failures, angiographic success rate was 96% among lesions for which RA was the primary intention. Complexity of cases was high (80.1% of RA lesions ACC/AHA type B2 or C). CONCLUSIONS A default radial approach is compatible with successful treatment of a wide range of coronary lesions, with a low incidence of crossover to femoral access. When the radial approach fails, it is usually due to access problems rather than issues of guide catheter handling and support.

Reduction in mortality and target-lesion revascularisation at 2 years: a comparison between drug-eluting stents and conventional bare-metal stents in the "real world".

BACKGROUND Long-term safety of drug-eluting stent (DES) is still a concern. We aimed to assess the impact of DES use on all-cause mortality and target-lesion revascularisation (TLR) in routine clinical practice. METHODS Retrospective analysis of all patients undergoing percutaneous coronary intervention with stent implantation at our institution between January 2003 and December 2004. To account for differences in patient characteristics, logistic regression was used to produce a propensity score for DES group membership. Patients receiving DES were then matched to patients receiving bare metal stents (BMS) with identical propensity scores. These two groups were then compared with respect to the incidence of TLR and all-cause mortality. RESULTS During the study period 995 patients received DES. Of these, 82 patients had combined DES and BMS use and were therefore excluded; leaving 913 DES patients compared to 2105 BMS patients. Patients who received DES were more likely to be diabetic, hypertensive, had more lesions treated, restenotic lesions treated, left anterior descending and left main stem interventions, long lesions treated, small diameter lesions treated, and American Heart Association C-type lesions treated. After performing propensity-matching, to account for differences in patient characteristics, we were able to successfully match 777 DES patients to 777 BMS patients. The TLR rates at 24 months were significantly lower for DES patients (DES-4.2% vs BMS-9.2%, p<0.001). All-cause mortality was also significantly lower for DES patients (DES-1.8% vs BMS-4.0%, p=0.01). CONCLUSIONS In routine clinical practice DES implantation continued to demonstrate a significant reduction in the need for repeat intervention at 24 months. All-cause and cardiac mortality was also significantly lower for DES patients compared to BMS patients.

The Impact of Diabetes Mellitus on Two-Year Mortality Following Contemporary Percutaneous Coronary Intervention: Implications for Revascularization Practice

OBJECTIVE To assess the impact of diabetes on 2-year mortality in current PCI practice. BACKGROUND In patients with coronary artery disease undergoing revascularization, diabetes mellitus is associated with higher mortality. METHODS A retrospective analysis was done of all patients undergoing PCI at our tertiary center between January 2000 and December 2004. There were 6,160 PCI procedures performed in 5,759 patients who received at least one stent. Of these patients, 801 (13.9%) were diabetic and 4,958 (86.1%) were nondiabetic. The primary outcome measure of the study was all-cause mortality. All patients were followed up for a period of 2 years. Multivariate logistic regression analysis was used to test for a potential independent association between diabetic status and follow-up mortality. RESULTS Before adjustment, a trend toward higher mortality was observed in diabetic patients compared to non-diabetics at 1 year (3.2% vs 2.4%) and 2 years (5.1% vs 3.8%), P = 0.12. Independent predictors for mortality were increasing age, renal dysfunction, peripheral vascular disease, NYHA class >2, urgent PCI, treating left main stem lesions, vessel diameter < or = 2.5 mm, and 3-vessel disease. The use of drug-eluting stent was associated with a reduction in mortality. Diabetes was found to have no independent impact on mortality following PCI (odds ratio = 1.08; 95% confidence intervals = 0.73-1.60; P = 0.71). CONCLUSION The presence of diabetes was not an independent predictor of mortality following PCI. A diabetic patient that does not require insulin treatment and has no evidence of macro- or microvascular diabetic disease could enjoy a PCI outcome similar to nondiabetic subjects.

Predicting angiographic outcome in contemporary percutaneous coronary intervention: a lesion-specific logistic model.

BACKGROUND Previous angiographic lesion classification systems were derived from analysis of outcomes and lesion complexity in the early stent era. Advances in equipment design and techniques have altered the association between lesion and target vessel characteristics and procedural outcome in modern percutaneous coronary intervention (PCI). We evaluated the precise relationship between lesion characteristics and technical outcome on a lesion by lesion basis in a large dataset. We developed a multivariate model to predict technical failure in PCI. METHODS Analysis of prospectively collected data on 10,800 lesions in 6,719 consecutive PCI cases between January 2000 and December 2004. Multivariate logistic regression was undertaken to identify predictors of angiographic outcome at each treated lesion (success/failure). Statistical model validation was carried out using data from a further 3,340 treated lesions in 1,940 consecutive cases. RESULTS Independent variables associated with an increased risk of technical failure included total occlusion, severe calcification, proximal vessel tortuosity >90 degrees, lesion in a degenerate vein graft, and lesion angulation > or =90 degrees. The receiver operating characteristics (ROC) curve for the predicted probability of technical failure was 0.85. Failure occurred in 2.2% of treated lesions in the validation set (ROC curve 0.82, model predicted 2.5%). CONCLUSIONS We have re-evaluated the association between lesion characteristics and technical outcome in modern PCI. We have thereby developed a contemporary prediction model for angiographic outcome at each treated lesion.

103 The ability of cardiogoniogmetry compared to flow fractional reserve at identifying physiologically significant coronary stenosis: the cardioflow study

Introduction Cardiogoniometry (CGM) is method of 3-dimensional electrocardiographic assessment which has been previously shown to identify patients with angiographically defined, stable coronary artery disease (CAD). However, angiographic evidence of CAD, does not always correlate to physiologically significant CAD. The aim of our study was to assess the ability of CGM to detect physiologically significant coronary stenosis defined by fractional flow reserve (FFR). Methods In a tertiary cardiology centre, patients with single vessel CAD were enrolled into a prospective double blinded observational study. A baseline CGM recording was performed at rest. A second CGM recording was then performed during the FFR procedure, at the time of maximal hyperaemia. A significant CGM result was defined as an automatically calculated ischaemia score<0 and a significant FFR ratio defined as<0.8. After enrolment, CGM and FFR results were compared and markers of diagnostic performance (sensitivity, specificity, positive predictive value and negative predictive value) were calculated at rest and during maximal hyperaemia. Statistical agreement between CGM and FFR was calculated by the Kappa statistic. Results Forty patients were included (aged 61.1±11.0; 60.0% male), of which sixteen (40%) were found to have significant CAD when assessed by FFR. Markers of diagnostic performance of CGM are shown in the table. Conclusion The diagnostic performance of CGM to detect physiologically significant stable CAD is poor at rest. Although, the diagnostic performance of CGM improves substantially during maximal hyperaemia, it does not reach sufficient levels of accuracy to be used routinely in clinical practice. Abstract 103 Table 1 CGM at rest (n= 40) CGM during maximal hyperaemia (n= 40) Sensitivity 31.3% 68.8% Specificity 62.5% 54.2% Positive predictive value 35.7% 50.0% Negative predictive value 57.7% 72.2% Kappa statistic for agreement −0.06, p=0.64 0.21, p=0.15