Role of Right Ventricular Strain Measured by Two-Dimensional Echocardiography in the Diagnosis of Cardiac Amyloidosis.

BACKGROUND: Cardiac amyloidosis (CA) causes restrictive cardiomyopathy usually associated with a poor prognosis. Two subtypes predominate: systemic light-chain CA (ALCA) and transthyretin-derived CA (either wild type transthyretin amyloidosis [TTRwt] or mutant transthyretin amyloidosis [TTRm]). Left ventricular (LV) apical sparing has been extensively studied using speckle-tracking echocardiography for diagnosis, but the right ventricular (RV) deformation pattern has not been described. The aims of this study were to characterize RV involvement in patients with CA and to identify parameters that may help in the differential diagnosis between ALCA and transthyretin-derived CA subtypes. METHODS: Seventy-eight patients with CA (47 with ALCA, 20 with TTRwt, and 11 with TTRm) and 24 healthy control subjects were included. Global longitudinal strain (GLS) was analyzed in 16 LV and six RV segments. LV and RV apical ratios (ARs) were obtained. GLS was expressed as an absolute value. RESULTS: LV GLS and free-wall RV longitudinal strain were impaired in all patients (LV GLS: 11.9 ± 2.9% in ALCA, 12.5 ± 3.8% in TTRwt, 14.9 ± 2.7% in TTRm, and 21.9 ± 2.6% in control subjects [P < .01]; free-wall RV longitudinal strain: 13.1 ± 6.8%, 14.9 ± 4.5%, 17.2 ± 3.4%, and 22.1 ± 3.1%, respectively [P < .01]). LV and RV ARs were higher in ALCA compared with both TTRwt, TTRm, and control subjects (LV AR: 1.1 ± 0.2, 0.8 ± 0.2, 0.9 ± 0.1, and 0.7 ± 0.1, respectively [P < .001]; RV AR: 1.1 ± 0.2, 0.6 ± 0.2, 0.6 ± 0.1, and 0.6 ± 0.1, respectively [P < .001]). Cutoff values of LV AR > 0.96 and RV AR > 0.8 showed high accuracy to differentiate between ALCA and transthyretin-derived CA. CONCLUSIONS: RV dysfunction is common in patients with CA. Analysis of RV strain showed an apical sparing pattern, as previously described in the left ventricle, with a higher AR as a specific finding in patients with ALCA. RV AR may be a parameter that can differentiate the subtypes of amyloidosis on the basis of speckle-tracking echocardiographic analysis.

Losartan Versus Atenolol for Prevention of Aortic Dilation in Patients With Marfan Syndrome.

BACKGROUND: Beta-blockers are the standard treatment in Marfan syndrome (MFS). Recent clinical trials with limited follow-up yielded conflicting results on losartan's effectiveness in MFS. OBJECTIVES: The present study aimed to evaluate the benefit of losartan compared with atenolol for the prevention of aortic dilation and complications in Marfan patients over a longer observation period (>5 years). METHODS: A total of 128 patients included in the previous LOAT (LOsartan vs ATenolol) clinical trial (64 in the atenolol and 64 in the losartan group) were followed up for an open-label extension of the study, with the initial treatment maintained. RESULTS: Mean clinical follow-up was 6.7 ± 1.5 years. A total of 9 events (14.1%) occurred in the losartan group and 12 (18.8%) in the atenolol group. Survival analysis showed no differences in the combined endpoint of need for aortic surgery, aortic dissection, or death (p = 0.462). Aortic root diameter increased with no differences between groups: 0.4 mm/year (95% confidence interval: 0.2 to 0.5) in the losartan and 0.4 mm/year (95% confidence interval: 0.3 to 0.6) in the atenolol group. In the subgroup analyses, no significant differences were observed considering age, baseline aortic root diameter, or type of dominant negative versus haploinsufficient FBN1 mutation. CONCLUSIONS: Long-term outcome of Marfan syndrome patients randomly assigned to losartan or atenolol showed no differences in aortic dilation rate or presence of clinical events between treatment groups. Therefore, losartan might be a useful, low-risk alternative to beta-blockers in the long-term management of these patients.

Usefulness of Two-Dimensional Strain Parameters to Diagnose Acute Rejection after Heart Transplantation.

BACKGROUND: Acute cellular rejection (ACR) is still a relevant complication after orthotopic heart transplantation. The diagnosis of ACR is based on endomyocardial biopsy (EMB). Recent advances in two-dimensional strain imaging may allow early noninvasive detection of ACR. The objective of this study was to analyze the usefulness of conventional and new echocardiographic parameters to exclude ACR after orthotopic heart transplantation. METHODS: Thirty-four consecutive adult heart transplant recipients admitted to a single center between January 2010 and December 2012 for orthotopic heart transplantation were prospectively included. A total of 235 pairs of EMB and echocardiographic examination were performed. A median of seven studies per patient (interquartile range, six to eight studies per patient) were performed during the first year of follow-up. Classic echocardiographic parameters; speckle-tracking-derived left ventricular (LV) longitudinal, radial, and circumferential strain; and global and free wall right ventricular (RV) longitudinal strain were analyzed. RESULTS: ACR was detected in 26.4% of EMB samples (n = 62); 5.1% (n = 12) required specific treatment (ACR degree ≥ 2R). Lower absolute values of global LV longitudinal strain and free wall RV longitudinal strain were present in patients with ACR degree ≥ 2R compared with those without ACR (13.7 ± 2.7% vs 17.8 ± 3.4% and 16.6 ± 3.6% vs 23.3 ± 5.2%, respectively). An average LV longitudinal strain < 15.5% had 85.7% sensitivity, 81.4% specificity, 98.8% negative predictive value, 25.0% positive predictive value, and 81.7% accuracy for the presence of ACR degree ≥ 2R. Free wall RV longitudinal strain < 17% had 85.7% sensitivity, 91.1% specificity, 98.8% negative predictive value, 42.9% positive predictive value, and 90.7% accuracy for ACR degree ≥ 2R. Both variables were normal in 106 echocardiograms (57.6%); none of these patients presented with ACR degree ≥ 2R. CONCLUSIONS: The combination of two new echocardiographic measures, global LV and RV free wall longitudinal strain, may be able to identify a group of heart transplant patients who are unlikely to have ACR. If these findings are confirmed independently, it may be possible to use LV and RV strain measures as reliable tools to exclude ACR and to reduce the burden of repeated EMB.

Noninvasive monitoring of serial changes in pulmonary vascular resistance and acute vasodilator testing using cardiac magnetic resonance.

OBJECTIVES: The study sought to evaluate the ability of cardiac magnetic resonance (CMR) to monitor acute and long-term changes in pulmonary vascular resistance (PVR) noninvasively. BACKGROUND: PVR monitoring during the follow-up of patients with pulmonary hypertension (PH) and the response to vasodilator testing require invasive right heart catheterization. METHODS: An experimental study in pigs was designed to evaluate the ability of CMR to monitor: 1) an acute increase in PVR generated by acute pulmonary embolization (n = 10); 2) serial changes in PVR in chronic PH (n = 22); and 3) changes in PVR during vasodilator testing in chronic PH (n = 10). CMR studies were performed with simultaneous hemodynamic assessment using a CMR-compatible Swan-Ganz catheter. Average flow velocity in the main pulmonary artery (PA) was quantified with phase contrast imaging. Pearson correlation and mixed model analysis were used to correlate changes in PVR with changes in CMR-quantified PA velocity. Additionally, PVR was estimated from CMR data (PA velocity and right ventricular ejection fraction) using a formula previously validated. RESULTS: Changes in PA velocity strongly and inversely correlated with acute increases in PVR induced by pulmonary embolization (r = -0.92), serial PVR fluctuations in chronic PH (r = -0.89), and acute reductions during vasodilator testing (r = -0.89, p ≤ 0.01 for all). CMR-estimated PVR showed adequate agreement with invasive PVR (mean bias -1.1 Wood units,; 95% confidence interval: -5.9 to 3.7) and changes in both indices correlated strongly (r = 0.86, p < 0.01). CONCLUSIONS: CMR allows for noninvasive monitoring of acute and chronic changes in PVR in PH. This capability may be valuable in the evaluation and follow-up of patients with PH.