F. David Fortuin

A simple method for noninvasive estimation of pulmonary vascular resistance

OBJECTIVES We sought to test whether the ratio of peak tricuspid regurgitant velocity (TRV, ms) to the right ventricular outflow tract time-velocity integral (TVI(RVOT), cm) obtained by Doppler echocardiography (TRV/TVI(RVOT)) provides a clinically reliable method to determine pulmonary vascular resistance (PVR). BACKGROUND Pulmonary vascular resistance is an important hemodynamic variable used in the management of patients with cardiovascular and pulmonary disease. Right-heart catheterization, with its associated disadvantages, is required to determine PVR. However, a reliable noninvasive method is unavailable. METHODS Simultaneous Doppler echocardiographic examination and right-heart catheterization were performed in 44 patients. The ratio of TRV/TVI(RVOT) was then correlated with invasive PVR measurements using regression analysis. An equation was modeled to calculate PVR in Wood units (WU) using echocardiography, and the results were compared with invasive PVR measurements using the Bland-Altman analysis. Using receiver-operating characteristics curve analysis, a cutoff value for the Doppler equation was generated to determine PVR >2WU. RESULTS As calculated by Doppler echocardiography, TRV/TVI(RVOT) correlated well (r = 0.929, 95% confidence interval 0.87 to 0.96) with invasive PVR measurements. The Bland-Altman analysis between PVR obtained invasively and that by echocardiography, using the equation: PVR = TRV/TVI(RVOT) x 10 + 0.16, showed satisfactory limits of agreement (mean 0 +/- 0.41). A TRV/TVI(RVOT) cutoff value of 0.175 had a sensitivity of 77% and a specificity of 81% to determine PVR >2WU. CONCLUSIONS Doppler echocardiography may provide a reliable, noninvasive method to determine PVR.

Phase 1/2 Placebo-Controlled, Double-Blind, Dose-Escalating Trial of Myocardial Vascular Endothelial Growth Factor 2 Gene Transfer by Catheter Delivery in Patients With Chronic Myocardial Ischemia

Background—This phase 1/2 study investigated the safety of percutaneous catheter-based gene transfer of naked plasmid DNA encoding for vascular endothelial growth factor 2 (phVEGF2) to left ventricular (LV) myocardium in a prospective, randomized, double-blind, placebo-controlled, dose-escalating study of inoperable patients with class III or IV angina. Methods and Results—A steerable deflectable 8F catheter with a 27-gauge needle at its distal tip was advanced percutaneously to the endocardial surface of the LV in 19 patients (age, 61±2 years) with chronic myocardial ischemia who were not candidates for conventional revascularization. Patients were randomized in a double-blind fashion to receive 6 injections (total volume, 6.0 mL) of placebo or phVEGF2 in doses of 200 &mgr;g (n=9), 800 &mgr;g (n=9), or 2000 &mgr;g (n=1) guided by LV electromechanical (NOGA) mapping with a gene-to-placebo ratio of 2:1. A total of 114 LV injections were delivered and caused no hemodynamic alterations, sustained ventricular arrhythmias, ECG evidence of infarction, or ventricular perforation. End-point analysis at 12 weeks disclosed a statistically significant improvement in Canadian Cardiovascular Society (CCS) angina class in phVEGF2-treated versus placebo-treated patients (−1.3 versus −0.1, P =0.04). Remaining efficacy end points—including change in exercise duration (91.8 versus 3.9 seconds), functional improvement by ≥2 CCS classes (9 of 12 versus 1 of 6), and Seattle Angina Questionnaire data—all showed strong trends favoring efficacy of phVEGF2 versus placebo treatment. Conclusions—This phase 1/2, double-blind, randomized trial provides preliminary data that support safety of phVEGF2 catheter-mediated myocardial gene transfer. The statistically significant reduction in anginal class and strong positive trends for remaining end points suggest that a larger phase 2/3 trial is warranted.

Intramyocardial, Autologous CD34+ Cell Therapy for Refractory Angina

Rationale: A growing number of patients with coronary disease have refractory angina. Preclinical and early-phase clinical data suggest that intramyocardial injection of autologous CD34+ cells can improve myocardial perfusion and function. Objective: Evaluate the safety and bioactivity of intramyocardial injections of autologous CD34+ cells in patients with refractory angina who have exhausted all other treatment options. Methods and Results: In this prospective, double-blind, randomized, phase II study (ClinicalTrials.gov identifier: NCT00300053), 167 patients with refractory angina received 1 of 2 doses (1×105 or 5×105 cells/kg) of mobilized autologous CD34+ cells or an equal volume of diluent (placebo). Treatment was distributed into 10 sites of ischemic, viable myocardium with a NOGA mapping injection catheter. The primary outcome measure was weekly angina frequency 6 months after treatment. Weekly angina frequency was significantly lower in the low-dose group than in placebo-treated patients at both 6 months (6.8±1.1 versus 10.9±1.2, P=0.020) and 12 months (6.3±1.2 versus 11.0±1.2, P=0.035); measurements in the high-dose group were also lower, but not significantly. Similarly, improvement in exercise tolerance was significantly greater in low-dose patients than in placebo-treated patients (6 months: 139±151 versus 69±122 seconds, P=0.014; 12 months: 140±171 versus 58±146 seconds, P=0.017) and greater, but not significantly, in the high-dose group. During cell mobilization and collection, 4.6% of patients had cardiac enzyme elevations consistent with non-ST segment elevation myocardial infarction. Mortality at 12 months was 5.4% in the placebo-treatment group with no deaths among cell-treated patients. Conclusions: Patients with refractory angina who received intramyocardial injections of autologous CD34+ cells (105 cells/kg) experienced significant improvements in angina frequency and exercise tolerance. The cell-mobilization and -collection procedures were associated with cardiac enzyme elevations, which will be addressed in future studies.

Transcatheter Amplatzer device closure of atrial septal defect and patent foramen ovale in patients with presumed paradoxical embolism.

OBJECTIVE To review our experience with, and profile the safety and efficacy of, the Amplatzer PFO (patent foramen ovale) occluder (APO) and Amplatzer septal occluder (ASO) used to close PFO and/or atrial septal defect (ASD) in patients with paradoxical embolism (PE). PATIENTS AND METHODS Between April 1998 and November 2002, 103 patients at the Mayo Clinic in Rochester, Minn, and Scottsdale, Ariz, mean age 52.4 years, with presumed PE (transient ischemic attack [n=22], stroke [n=77], or peripheral emboli [n=4]) underwent transcatheter device closure of PFO (n=81), ASD (n=12), and ASD/PFO (n=10) with 106 devices (APO [n=22] or ASO [n=84]). RESULTS All devices deployed successfully, and no patients died. Procedural complications included atrial fibrillation (n=2), vessel injury (n=3), profound sinus node dysfunction (n=1), and device embolization with successful retrieval (n=1). At 3 months, 7 of 95 monitored patients had trivial residual shunt; at 12 months, 2 of 28 monitored patients had trivial residual shunt. Three patients had recurrent events--2 transient ischemic attacks and 1 retinal artery occlusion--at a mean +/- SD follow-up of 8.3 +/- 8.1 months (range, 1-34 months). None of these 3 patients had residual shunt or evidence of intracardiac thrombus. The average annual recurrence of all events was 3.6% at 23 months. The overall mean +/- SD freedom from recurrence of all events was 98.9% +/- 1.2% and 83.8% +/- 10.2% at 12 and 29 months of follow-up, respectively. CONCLUSIONS Transcatheter device closure of PFO and/or ASD with use of APO/ASO in patients with presumed PE is effective and safe. Recurrent events may occur in the absence of a residual shunt.

A phase 3, randomized, double-blinded, active-controlled, unblinded standard of care study assessing the efficacy and safety of intramyocardial autologous cd34+ cell administration in patients with refractory angina: Design of the renew study

Preclinical trials indicate that CD34+ cells represent an effective angiogenic stem cell component. Early-phase clinical trials suggest that intramyocardial administration of autologous CD34+ cells may improve functional capacity and symptoms of angina. RENEW is a pivotal phase 3 trial designed to determine the efficacy of granulocyte colony-stimulating factor (G-CSF)-mobilized CD34+ stem cells for the treatment for patients with refractory angina and chronic myocardial ischemia. Patients (n = 444) receiving maximally tolerated antianginal therapies and lacking conventional revascularization options with Canadian Cardiovascular Society class III or IV angina and ischemia on stress testing will be randomized 2:1:1 to cell therapy (G-CSF-mediated stem cell mobilization, apheresis, and intramyocardial injection of 1 × 10(5) autologous CD34(+) cells/kg), active control (G-CSF-mediated stem cell mobilization, apheresis, and intramyocardial placebo injection), or open-label standard of care. The primary efficacy end point is change in exercise treadmill time in the treated vs active control patients, with 90% power to detect a 60-second difference in exercise time between cell-treated (n = 200) and active control (n = 100) patients. Key secondary end points include total number of anginal episodes per week and the incidence of independently adjudicated major adverse cardiac events and serious adverse events. RENEW will be the first adequately powered study aimed at definitively determining the efficacy of a cell therapy (intramyocardially delivered autologous CD34+ cells) for improvement of functional capacity in patients with refractory angina.

A double-blind, randomized, controlled, multicenter study to assess the safety and cardiovascular effects of skeletal myoblast implantation by catheter delivery in patients with chronic heart failure after myocardial infarction.

BACKGROUND We sought to determine the safety and preliminary efficacy of transcatheter intramyocardial administration of myoblasts in patients with heart failure (HF). METHODS MARVEL is a randomized placebo-controlled trial of image-guided, catheter-based intramyocardial injection of placebo or myoblasts (400 or 800 million) in patients with class II to IV HF and ejection fraction <35%. Primary end points were frequency of serious adverse events (safety) and changes in 6-minute walk test and Minnesota Living With HF score (efficacy). Of 330 patients intended for enrollment, 23 were randomized (MARVEL-1) before stopping the study for financial reasons. RESULTS At 6 months, similar numbers of events occurred in each group: 8 (placebo), 7 (low dose), and 8 (high dose), without deaths. Ventricular tachycardia responsive to amiodarone was more frequent in myoblast-treated patients: 1 (placebo), 3 (low dose), and 4 (high dose). A trend toward improvement in functional capacity was noted in myoblast-treated groups (Δ6-minute walk test of -3.6 vs +95.6 vs +85.5 m [placebo vs low dose vs high dose; P = .50]) without significant changes in Minnesota Living With HF scores. CONCLUSIONS In HF patients with chronic postinfarction cardiomyopathy, transcatheter administration of myoblasts in doses of 400 to 800 million cells is feasible and may lead to important clinical benefits. Ventricular tachycardia may be provoked by myoblast injection but appears to be a transient and treatable problem. A large-scale outcome trial of myoblast administration in HF patients with postinfarction cardiomyopathy is feasible and warranted.

Dual Versus Single Antiplatelet Therapy in Patients Undergoing Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-analysis

BACKGROUND Although dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is a widely accepted strategy in patients undergoing transcatheter aortic valve replacement (TAVR), this approach is not evidence based. We therefore sought to systematically review the current evidence for this practice in terms of 30-day outcome looking at stroke, MI, bleeding, and death. METHODS Relevant studies were identified through electronic literature search. Studies involving single antiplatelet therapy (SAPT) and DAPT in patients undergoing TAVR were included. Study specific risk ratios were calculated and combined using random-effects model meta-analysis. RESULTS Analysis of data from 410 patients, stroke occurred in seven (3.16%) of SAPT and six (3.17%) of DAPT RR=1.03 (95% CI, 0.36-2.96, P=0.96). In analysis of 530 patients, MI occurred in three (1.07%) of SAPT and one (0.40%) of DAPT RR=1.97 (95% CI, 0.29-13.29, P=0.49), significant bleeding (major, life threatening and bleeding requiring transfusion) occurred in 20 (7.11%) of SAPT and 43 (17.27%) of DAPT RR=0.41 (95% CI, 0.25-0.69, P=0.0006). Number needed to harm for major or life threatening bleeding was 10. Death occurred in 15 (6.78%) of SAPT and 15 (7.94%) of DAPT (RR 0.91; 95% CI 0.46-1.79, P=0.78). CONCLUSION Our meta-analysis suggests that at 30 days following TAVR there is no difference between post-procedural SAPT versus DAPT for the risk of stroke or MI and DAPT may have a higher bleeding risk. Adequately powered RCTs are warranted to clarify the optimal antiplatelet treatment strategy following TAVR.

Shorter (≤6 months) versus longer (≥12 months) duration dual antiplatelet therapy after drug eluting stents: A meta-analysis of randomized clinical trials

Optimal duration of dual antiplatelet therapy (DAPT), defined as use of both aspirin and a P2Y12 receptor inhibitor, after implantation of drug eluting stents (DES) is still subject of ongoing debate. We systematically review efficacy and safety of ≤6 months versus ≥12 months DAPT after implantation of DES.

Autologous CD34+ cell therapy for refractory angina: 2-year outcomes from the ACT34-CMI study

An increasing number of patients have refractory angina despite optimal medical therapy and are without further revascularization options. Preclinical studies indicate that human CD34+ stem cells can stimulate new blood vessel formation in ischemic myocardium, improving perfusion and function. In ACT34-CMI (N = 167), patients treated with autologous CD34+ stem cells had improvements in angina and exercise time at 6 and 12 months compared to placebo; however, the longer-term effects of this treatment are unknown. ACT34 was a phase II randomized, double-blind, placebo-controlled clinical trial comparing placebo, low dose (1 × 105 CD34/kg body weight), and high dose (5 × 105 CD34/kg) using intramyocardial delivery into the ischemic zone following NOGA® mapping. To obtain longer-term safety and efficacy in these patients, we compiled data of major adverse cardiac events (MACE; death, myocardial infarction, acute coronary syndrome, or heart failure hospitalization) up to 24 months as well as angina and quality of life assessments in patients who consented for 24-month follow-up. A total of 167 patients with class III–IV refractory angina were randomized and completed the injection procedure. The low-dose-treated patients had a significant reduction in angina frequency (p = 0.02, 0.035) and improvements in exercise tolerance testing (ETT) time (p = 0.014, 0.017) compared to the placebo group at 6 and 12 months. At 24 months, patients treated with both low-and high-dose CD34+ cells had significant reduction in angina frequency (p = 0.03). At 24 months, there were a total of seven deaths (12.5%) in the control group versus one (1.8%) in the low-dose and two (3.6%) in the high-dose (p = 0.08) groups. At 2 years, MACE occurred at a rate of 33.9%, 21.8%, and 16.2% in control, low-, and high-dose patients, respectively (p = 0.08). Autologous CD34+ cell therapy was associated with persistent improvement in angina at 2 years and a trend for reduction in mortality in no-option patients with refractory angina.

Preventive PCI versus culprit lesion stenting during primary PCI in acute STEMI: a systematic review and meta-analysis

Aim The benefit of preventive percutaneous coronary intervention (PCI) in ST elevation myocardial infarction (STEMI) has been shown in randomised trials. However, all the randomised trials are underpowered to detect benefit in cardiac death. We aim to systematically review evidence on the cardiac mortality benefit of preventive PCI in patients presenting with acute STEMI in randomised patient populations. Methods PubMed, Scopus, Cochrane and clinicaltrials.gov databases were searched for studies published until 30 September 2013. The studies were limited to randomised clinical trials. Independent observers abstracted the data on outcomes, characteristics and qualities of studies included. Fixed effect model was employed for meta-analysis. Heterogeneity of studies included was analysed using I2 statistics. Results In three randomised clinical trials published, involving 748 patients with acute STEMI and multivessel disease, 416 patients were randomised to preventive PCI and 332 to culprit-only PCI. Patients undergoing preventive PCI had significant lower risk of cardiovascular deaths (pooled OR 0.39, 95% CI 0.18 to 0.83, p=0.01, I2=0%), repeat revascularisation (pooled OR 0.28, 95% CI 0.18 to 0.44, p=0.00001, I2=0%) and non-fatal myocardial infarction (pooled OR 0.38, 95% CI 0.20 to 0.75, p=0.005, I2=0%) compared with culprit-only revascularisation. Conclusions In patients presenting with acute STEMI and significant multivessel coronary artery disease, based on our data, preventive PCI is associated with lower risk of cardiovascular mortality compared with primary PCI of only the culprit artery. This finding needs to be confirmed in larger adequately powered randomised clinical trials.