International Journal of Cardiology

International Journal of Cardiology | Vol. 5, No. 8, August 2014 | pp. 57–64

DOI: 10.46882/2014/IJC/000065

Original Research Article

Prognostic Impact of Moderate Paravalvular Regurgitation After Transcatheter Aortic Valve Implantation

Jean-Pierre Dubois¹, Pierre Vigneron¹, Lucia Rossi²

¹Department of Interventional Cardiology, Hôpital Européen Georges-Pompidou, Paris, France

²Department of Cardiac Surgery, University of Milan, Milan, Italy

Abstract:
Transcatheter aortic valve implantation (TAVI) is an established alternative to surgery for high-risk patients with severe aortic stenosis. However, paravalvular regurgitation (PVR) remains a common post-procedural finding due to calcific asymmetry. This study investigated the 3-year prognostic impact of post-procedural moderate PVR on mortality and heart failure hospitalization. We prospectively followed 240 consecutive high-risk patients who underwent successful TAVI with early-generation balloon-expandable or self-expanding valves. Post-procedural PVR severity was graded using multi-parametric transthoracic echocardiography at discharge. The primary endpoint was a composite of all-cause mortality or heart failure hospitalization at 36 months. Moderate PVR was identified in 38 patients (15.8%), while 202 patients had none, trace, or mild PVR. At 3 years, the primary composite endpoint occurred significantly more frequently in the moderate PVR cohort than in the trace-to-mild group (47.4% vs. 21.8%, log-rank p < 0.001). This difference was driven by both higher all-cause mortality (28.9% vs. 12.4%, p = 0.01) and recurrent heart failure hospitalizations (36.8% vs. 14.9%, p < 0.01). Multivariable Cox proportional hazards analysis confirmed that post-procedural moderate PVR was an independent predictor of the 3-year composite endpoint (hazard ratio: 2.34, 95% CI: 1.41–3.88, p = 0.001). Post-procedural moderate paravalvular regurgitation significantly compromises 3-year survival and survival freedom from heart failure hospitalizations after TAVI, underscoring the importance of deploying next-generation anti-leak valve designs.

Keywords: Aortic stenosis, Transcatheter aortic valve implantation, Paravalvular regurgitation, Echocardiography, Mortality, Long-term outcomes

Received: May 12, 2014; Revised: June 25, 2014; Accepted: July 14, 2014; Published: August 20, 2014

Citation: International Journal of Cardiology, 2014, Vol. 5, No. 8, pp. 57–64, DOI: 10.46882/2014/IJC/000065

International Journal of Cardiology | Vol. 5, No. 3, March 2014 | pp. 17–24

DOI: 10.46882/2014/IJC/000060

Original Research Article

Diagnostic Performance of Fractional Flow Reserve derived from Computed Tomography in Patients with Calcified Coronary Arteries

Arjun Patel¹, Rohan Mehta¹, Vikram Singh²

¹Department of Cardiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India

²Division of Cardiovascular Radiology, All India Institute of Medical Sciences, New Delhi, India

Abstract:
Computed tomography coronary angiography (CTCA) exhibits limited diagnostic specificity in patients with heavy coronary calcification due to blooming artifacts that obscure luminal narrowings. Fractional flow reserve computed from CTCA datasets (FFR-CT) integrates computational fluid dynamics to evaluate lesion-specific ischemia non-invasively. This study evaluated the diagnostic accuracy of FFR-CT for identifying hemodynamically significant lesions specifically in patients with high coronary artery calcium (CAC) scores. We prospectively enrolled 110 symptomatic patients with intermediate coronary stenoses and an Agatston CAC score greater than 400 who were scheduled for invasive coronary angiography and fractional flow reserve (FFR). FFR-CT was computed off-line using specialized processing software. Ischemia was defined as an invasive FFR less than or equal to 0.80. On a vessel-based analysis (134 vessels total), invasive FFR confirmed lesion-specific ischemia in 42 vessels (31.3%). FFR-CT demonstrated a diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of 85.7% (95% CI: 71.5%–94.6%), 81.5% (95% CI: 72.1%–88.9%), 67.9% (95% CI: 53.7%–80.1%), and 92.6% (95% CI: 84.6%–97.2%), respectively. The area under the receiver operating characteristic curve for FFR-CT was significantly superior to standard anatomical CTCA luminal assessment alone (0.87 vs. 0.64, p < 0.01). FFR-CT maintains high diagnostic accuracy and strong negative predictive value for identifying hemodynamically significant coronary stenoses even in the presence of severe calcification, reducing unnecessary diagnostic invasive angiograms in this challenging clinical cohort.

Keywords: Computed tomography coronary angiography, Fractional flow reserve, Coronary calcification, Computational fluid dynamics, Myocardial ischemia, Diagnostic accuracy

Received: December 05, 2013; Revised: January 18, 2014; Accepted: February 11, 2014; Published: March 20, 2014

Citation: International Journal of Cardiology, 2014, Vol. 5, No. 3, pp. 17–24, DOI: 10.46882/2014/IJC/000060

International Journal of Cardiology | Vol. 5, No. 5, May 2014 | pp. 33–40

DOI: 10.46882/2014/IJC/000062

Original Research Article

Comparison of Low-Dose versus Standard-Dose Anticoagulation After Mechanical Mitral Valve Replacement

Ahmed Al-Hassan¹, Fatima Al-Sayed¹, Sami Al-Otaibi²

¹Department of Cardiology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia

²Division of Cardiac Surgery, King Abdulaziz Medical City, Riyadh, Saudi Arabia

Abstract:
Mechanical mitral valve replacement demands lifelong oral anticoagulation with vitamin K antagonists to prevent thromboembolic complications. However, standard-intensity regimens are associated with significant bleeding risks. This randomized, open-label trial compared the safety and efficacy of a lower-intensity warfarin regimen versus the standard-intensity regimen in patients undergoing mechanical mitral valve replacement. We randomized 280 stable patients post-mitral valve replacement into two groups: the low-intensity group (target international normalized ratio [INR] 2.0–2.5, n = 140) or the standard-intensity group (target INR 2.5–3.5, n = 140). The primary safety endpoint was the 24-month incidence of major bleeding according to ISTH criteria, and the primary efficacy endpoint was a composite of thromboembolism, valve thrombosis, or ischemic stroke. At 24 months, the incidence of major bleeding was significantly lower in the low-intensity INR group than in the standard-intensity group (3.6% vs. 9.3%, hazard ratio: 0.38, 95% CI: 0.16–0.90, p = 0.02). The primary efficacy endpoint of thromboembolic events did not differ significantly between the cohorts (low-intensity: 2.1% vs. standard-intensity: 1.4%, hazard ratio: 1.48, 95% CI: 0.28–7.84, p = 0.64). Intracranial hemorrhage was completely absent in the lower-intensity cohort. A lower-intensity warfarin regimen targeting an INR of 2.0–2.5 safely reduces major bleeding complications compared to standard-intensity anticoagulation without a significant increase in thromboembolic risks in patients with mechanical mitral valves.

Keywords: Mechanical heart valve, Mitral valve replacement, Warfarin, Anticoagulation, International normalized ratio, Major bleeding

Received: February 02, 2014; Revised: March 15, 2014; Accepted: April 08, 2014; Published: May 20, 2014

Citation: International Journal of Cardiology, 2014, Vol. 5, No. 5, pp. 33–40, DOI: 10.46882/2014/IJC/000062

International Journal of Cardiology | Vol. 5, No. 11, November 2014 | pp. 81–88

DOI: 10.46882/2014/IJC/000068

Original Research Article

Prognostic Value of Right Ventricular Global Longitudinal Strain in Patients with Dilated Cardiomyopathy

Vasily Smirnov¹, Elena Kuzmina², Dmitry Ivanov¹

¹Department of Cardiology, Almazov National Medical Research Centre, St. Petersburg, Russia

²Division of Cardiovascular Imaging, Pavlov First Saint Petersburg State Medical University, St. Petersburg, Russia

Abstract:
While left ventricular parameters are traditionally prioritized in dilated cardiomyopathy (DCM), right ventricular (RV) function also independently impacts outcomes. This prospective study evaluated the long-term prognostic utility of right ventricular global longitudinal strain (RV-GLS) measured via speckle-tracking echocardiography in adult patients with DCM. We followed 185 stable DCM patients with a resting left ventricular ejection fraction (LVEF) less than 40%. Standard echocardiography quantified right ventricular fractional area change (FAC), and off-line deformation analysis measured absolute RV-GLS. The primary endpoint was a composite of cardiac mortality, urgent heart transplantation, or heart failure hospitalization over a 3-year follow-up period. Over a median follow-up of 34 months, 52 patients (28.1%) reached the primary endpoint. An impaired absolute baseline RV-GLS (defined as less than 15.5%) was strongly associated with a higher event rate. Kaplan-Meier analysis confirmed a significantly lower event-free survival rate in the low RV-GLS group (log-rank p < 0.001). After adjusting for age, NYHA class, LVEF, and NT-proBNP levels, multivariable Cox proportional hazards regression confirmed that an absolute RV-GLS less than 15.5% remained an independent predictor of the composite clinical endpoint (hazard ratio: 2.12, 95% CI: 1.28–3.52, p = 0.003). Conventional RV FAC did not retain independent predictive value in the fully adjusted model. Right ventricular global longitudinal strain is a powerful independent predictor of long-term clinical worsening in dilated cardiomyopathy, outperforming standard volumetric metrics.

Keywords: Dilated cardiomyopathy, Right ventricular function, Speckle-tracking echocardiography, Longitudinal strain, Prognosis, Heart failure

Received: August 12, 2014; Revised: September 24, 2014; Accepted: October 14, 2014; Published: November 20, 

International Journal of Cardiology | Vol. 5, No. 1, January 2014 | pp. 1–8

DOI: 10.46882/2014/IJC/000058

Original Research Article

Comparison of High-Dose versus Standard-Dose Clopidogrel in Patients with High Post-Treatment Platelet Reactivity Undergoing PCI

Ji-Hoon Kim¹, Min-Soo Park¹, Sung-Hoon Choi²

¹Department of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, South Korea

²Division of Electrophysiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea

Abstract:
High post-treatment platelet reactivity (HPPR) following standard clopidogrel therapy is associated with an increased risk of ischemic events after percutaneous coronary intervention (PCI). Adjusting the antiplatelet regimen based on platelet function testing could mitigate this risk. This randomized open-label trial evaluated whether a high-dose clopidogrel regimen reduces major adverse cardiovascular events (MACE) in patients with documented HPPR undergoing PCI. We screened 650 patients scheduled for elective PCI using the VerifyNow P2Y12 assay. HPPR was defined as a P2Y12 reaction unit (PRU) value greater than 230. A total of 180 patients identified with HPPR were randomized 1:1 to either the high-dose group (clopidogrel 150 mg daily, n = 90) or the standard-dose group (clopidogrel 75 mg daily, n = 90) for 6 months. The primary endpoint was a composite of cardiac death, non-fatal myocardial infarction, or definite stent thrombosis at 6 months. At 6 months, high-dose clopidogrel significantly reduced the mean PRU value from 265 ± 24 to 192 ± 31 (p < 0.001), whereas platelet reactivity remained elevated in the standard-dose group (258 ± 22 PRU). The primary composite endpoint occurred in 4.4% of the high-dose cohort compared to 12.2% of the standard-dose cohort (p = 0.04). No significant difference was observed in the incidence of TIMI major bleeding complications (2.2% vs. 1.1%, p = 0.56). Adjusting to a high-dose clopidogrel maintenance regimen in patients with verified high post-treatment platelet reactivity significantly enhances platelet inhibition and safely reduces short-term ischemic events following PCI.

Keywords: Percutaneous coronary intervention, Clopidogrel, Platelet reactivity, VerifyNow, Stent thrombosis, Antiplatelet therapy

Received: October 10, 2013; Revised: November 24, 2013; Accepted: December 15, 2013; Published: January 18, 2014

Citation: International Journal of Cardiology, 2014, Vol. 5, No. 1, pp. 1–8, DOI: 10.46882/2014/IJC/000058

International Journal of Cardiology | Vol. 5, No. 9, September 2014 | pp. 65–72

DOI: 10.46882/2014/IJC/000066

Original Research Article

Association Between Left Atrial Strain and Recurrence of Atrial Fibrillation Post-Catheter Ablation

Sven Lindstrom¹, Ingrid Johansson¹, Anders Nielsen²

¹Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden

²Department of Clinical Physiology, Aarhus University Hospital, Aarhus, Denmark

Abstract:
Catheter ablation using pulmonary vein isolation is an effective rhythm control strategy for paroxysmal atrial fibrillation (AF), but anatomical left atrial (LA) diameter alone poorly predicts recurrence. Left atrial reservoir strain (LA-RS) evaluated by speckle-tracking echocardiography offers a direct indicator of structural remodeling and compliance. This study investigated the independent association between baseline LA-RS and long-term arrhythmia recurrence post-catheter ablation. We prospectively enrolled 150 patients with symptomatic paroxysmal AF scheduled for radiofrequency catheter ablation. LA-RS was analyzed off-line using apical four- and two-chamber views before the intervention. The primary endpoint was any documented recurrence of atrial tachyarrhythmia lasting longer than 30 seconds after a 90-day blanking period over a 24-month follow-up. Arrhythmia recurrence occurred in 48 patients (32.0%). Baseline mean LA-RS was significantly lower in patients with recurrent events compared to those who maintained sinus rhythm (18.4% ± 3.2% vs. 28.5% ± 4.1%, p < 0.001). Multivariable Cox proportional hazards regression identified a depressed baseline LA-RS (absolute value less than 20%) as a powerful independent predictor of AF recurrence (hazard ratio: 2.45, 95% CI: 1.34–4.48, p = 0.003), whereas conventional LA volume indexing lost statistical significance. No major procedural access complications occurred. Left atrial reservoir strain is strongly and independently associated with atrial fibrillation recurrence following catheter ablation, outperforming traditional volumetric metrics for predicting long-term rhythm stability.

Keywords: Atrial fibrillation, Catheter ablation, Speckle-tracking echocardiography, Left atrial strain, Recurrence, Remodeling

Received: June 02, 2014; Revised: July 19, 2014; Accepted: August 08, 2014; Published: September 15, 2014