Safety and utility of dobutamine and pressure wire use in the hemodynamic assessment of low-flow, low-gradient aortic stenosis with reduced left ventricular ejection fraction.

BACKGROUND: The ACC/AHA guidelines recommend low-dose dobutamine challenge for hemodynamic assessment of the severity of AS in patients with low flow, low gradient aortic stenosis with reduced ejection fraction (EF) (LFLG-AS; stage D2). Inherent pitfalls of echocardiography could result in inaccurate aortic valve areas (AVA), which have downstream prognostic implications. Data on the safety and efficacy of coronary pressure wire and fluid-filled catheter use for low dose dobutamine infusion is sparse. METHODS: We retrospectively analyzed 39 consecutive patients with EF<50%, AVA<1cm2 and SVI<35ml/m2 on echocardiography who underwent simultaneous right and left heart catheterization. Hemodynamic assessments were performed at baseline and at every increment in the dobutamine infusion rate (The infusion was continued until maximal dose of dobutamine or a mean AV gradient>40mmHg was attained. The occurrence of sustained ventricular arrhythmias, symptomatic hypotension or intolerable symptoms leading to cessation of infusion was recorded. Transient ischemic attacks (TIAs) or clinically apparent strokes periprocedurally or up to 30days after the procedure were recorded. RESULTS: Dobutamine challenge confirmed true AS in 26 patients (67%) and pseudosevere AS in 34%. No sustained arrhythmias, hypotension or cessation of infusion from intolerable symptoms were observed. No clinical strokes or TIAs were observed up to 30days after procedure in any of these patients. CONCLUSIONS: Hemodynamic assessment of AS using a pressure wire with dobutamine challenge is a safe and effective tool in identifying truly severe AS in patients with LFLG-AS with reduced EF.

Impact of Catheterization Lab Computer Software Settings on Hemodynamic Assessment of Aortic Stenosis.

BACKGROUND: Accurate assessment of Cardiac Output (CO) is a critical measurement in the calculation of aortic valve area (AVA). Due to the known inaccuracy of estimated Fick calculations, many measure thermodilution (TD) CO as well due to previous studies showing better correlation with the gold standard direct CO. Previous studies showed suboptimal correlation between both methods. Most physicians assume that the TD CO is chosen by catheterization laboratory software for AVA evaluation. Our study was performed to check which CO method is assigned by our popular computer software system [Philips Xper Connect (XIM)] for the AVA calculation and the impact of that on clinical decision. METHODS: We studied one hundred consecutive patients who underwent right and left heart catheterization from 2009 to 2012 for assessment of AVA and who had both estimated Fick and TD CO calculated. Correlation of direct continuous VO2, assumed VO2 and TD based CO measurements were assessed by linear regression analysis and by variance component analysis. RESULTS: We found that whichever CO calculation was entered first to the software system became the determinative output used to calculate the AVA appearing on the final report. This was the estimated Fick method in 32 patients and TD in 68 patients. The CO used for the final report depended solely on the timing of the oxygen saturation samples. The Correlation between AVA based on both methods correlated poorly (Pearson R=0.73, Intra-Class Correlation (ICC) =0.72). This discrepancy affects recommendation for surgery (AVA <1.0 cm2) in 18 cases (18% of patients). CONCLUSION: Our widely used software has an arbitrary method of selecting the determinative CO to calculate the final AVA. For TD CO to 'trump' the Fick CO a complex series of computer commands needs to be performed. None of the physicians or technicians was aware of this software selection process, which affects critical treatment decisions.

The Impact of Direct Cardiac Output Determination On Using A Widely Available Direct Continuous Oxygen Consumption Measuring Device On The Hemodynamic Assessment of Aortic Valve.

BACKGROUND: Accurate assessment of cardiac output (CO) is essential for the hemodynamic assessment of aortic valve area (AVA). Estimation of oxygen consumption (VO2) and Thermodilution (TD) is employed in many cardiac catheterization laboratories (CCL) given the historically cumbersome nature of direct continuous VO2 measurement, the "gold standard" for this technique. A portable facemask device simplifies the direct continuous measurement of VO2, allowing for relatively rapid and continuous assessment of CO and AVA. METHODS AND MATERIALS: Seventeen consecutive patients undergoing right heart catheterization had simultaneous determination of CO by both direct continuous and assumed VO2 and TD. Assessments were only made when a plateau of VO2 had occurred. All measurements of direct continuous and assumed VO2, as well as, TD CO were obtained in triplicate. RESULTS: Direct continuous VO2 CO and assumed VO2 CO correlated poorly (R= 0.57; ICC =0.59). Direct continuous VO2 CO and TD CO also correlated poorly (R= 0.51; ICC=0.60). Similarly AVA derived from direct continuous VO2 correlated poorly with those of assumed VO2 (R= 0.68; ICC=0.55) and TD (R=0.66, ICC=0.60). Repeated direct continuous VO2 CO and AVA measurements were extremely correlated and reproducible [(R=0.93; ICC=0.96) and (R=0.99; ICC>0.99) respectively], suggesting that this was the most reliable measurement of CO. CONCLUSIONS: CO calculated from direct continuous VO2 measurement varies substantially from both assumed VO2 and TD based CO, which are widely used in most CCL. These differences may significantly impact the CO and AVA measurements. Furthermore, continuous, rather than average, measurement of VO2 appears to give highly reproducible results.

Cost-effectiveness of transcatheter versus surgical management of structural heart disease.

Transcatheter management of valvular and structural heart disease is the most growing aspect of interventional cardiology. While the early experience was limited to patients who were not candidate for surgery, the continuous improvement in the efficacy and safety expanded its use to different degree depending on the procedure and the disease involved. The cost of these procedures is a major concern for health care in developed world. Cost-effectiveness of these transcatheter structural procedures varies depending on the procedure itself, the burden of the underlying disease, the feasibility and cost of both the Transcatheter and surgical procedures. In this review, we turn now to a specific discussion of the medical economics of percutaneous valvular and structural interventions.

Cost-effectiveness of medical, endovascular and surgical management of peripheral vascular disease.

Peripheral arterial disease (PAD) is responsible for 20% of all US hospital admissions. Management of PAD has evolved over time to include many medical and transcatheter interventions in addition to the traditional surgical approach. Non-invasive interventions including supervised exercise programs and antiplatelets use are economically attractive therapies that should be considered in all patients at risk. While surgery offers so far a clinically and economically appropriate option, the improvement of percutaneous transluminal angioplasty (PTA) technique with the addition of drug-coated balloons offers a reasonably clinically and economically attractive alternative that will continue to evolve in the future.

Cost Effectiveness of Antiplatelet and Antithrombotic Therapy in the Setting of Acute Coronary Syndrome: Current Perspective and Literature Review.

Acute coronary syndromes (ACS) are associated with high rates of morbidity and mortality. The advances of antiplatelet and anticoagulation therapy over several years time have resulted in improved in cardiac outcomes, but with increased health care costs. Multiple cost-effectiveness studies have been performed to evaluate the use of available antiplatelet agents and anticoagulation in the setting of both ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Early on, the use of glycoprotein IIb/IIIa receptor inhibitors (GPIs) proved to be economically attractive in the management of ACS; however, the introduction of P2Y12 receptor antagonists limited their use to a bail out agents in complex interventions. Generic clopidogrel is probably still an economically attractive P2Y12 receptor antagonist choice, especially in low-risk ACS, while both ticagrelor and prasugrel present an economically attractive alternative option, especially in high-risk ACS and patients at risk for stent thrombosis. While enoxaparin presents an economically dominant alternative to heparin in NSTE-ACS, its role in STEMI in the contemporary era is unclear. During percutaneous coronary intervention (PCI), bivalirudin monotherapy was shown to be an economically dominant alternative to the combination of heparin and GPI in ACS. However, new studies may suggest that using heparin monotherapy may offer an attractive alternative. The comparative and cost effectiveness of different combinations of antiplatelet and antithrombotic therapy will be the focus of future expected clinical and economic assessments.

Comparative effectiveness of revascularization strategies in stable ischemic heart disease: current perspective and literature review.

Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are established strategies for coronary revascularization in the setting of ischemic heart disease. Multiple randomized controlled trials and observational studies have compared the impact of the two modalities on the patients' quality of life, mortality and morbidity, as well as the cost-effectiveness of these modalities in different clinical setting. CABG is the preferred strategy for revascularizations in patients with multi-vessel disease, especially in those with higher risk secondary to associated diabetes, left ventricular dysfunction or more complex lesions. PCI is a reasonable revascularization modality in patients with ischemia and single or low-risk multi-vessel disease and those with unprotected left main with low complexity anatomy. Compared with PCI, CABG is associated with less repeat revascularization, better quality of life and improved survival in high-risk patients. Although CABG is associated with higher cost, it is probably associated with a reasonable cost per quality-adjusted life-year gained in many patients. Therefore, CABG will often be a cost-effective strategy, especially in patients with high angiographic complexity and/or diabetes.