Impact of a Geometric Correction for Proximal Flow Constraint on the Assessment of Mitral Regurgitation Severity Using the Proximal Flow Convergence Method

BACKGROUND: Overestimation of the severity of mitral regurgitation (MR) by the proximal isovelocity surface area (PISA) method has been reported. We sought to test whether angle correction (AC) of the constrained flow field is helpful to eliminate overestimation in patients with eccentric MR. METHODS: In a total of 33 patients with MR due to prolapse or flail mitral valve, both echocardiography and cardiac magnetic resonance image (CMR) were performed to calculate regurgitant volume (RV). In addition to RV by conventional PISA (RV(PISA)), convergence angle (α) was measured from 2-dimensional Doppler color flow maps and RV was corrected by multiplying by α/180 (RV(AC)). RV measured by CMR (RV(CMR)) was used as a gold standard, which was calculated by the difference between total stroke volume measured by planimetry of the short axis slices and aortic stroke volume by phase-contrast image. RESULTS: The correlation between RV(CMR) and RV by echocardiography was modest [RV(CMR) vs. RV(PISA) (r = 0.712, p < 0.001) and RV(CMR) vs. RV(AC) (r = 0.766, p < 0.001)]. However, RV(PISA) showed significant overestimation (RV(PISA) - RV(CMR) = 50.6 ± 40.6 mL vs. RV(AC) - RV(CMR) = 7.7 ± 23.4 mL, p < 0.001). The overall accuracy of RV(PISA) for diagnosis of severe MR, defined as RV ≥ 60 mL, was 57.6% (19/33), whereas it increased to 84.8% (28/33) by using RV(AC) (p = 0.028). CONCLUSION: Conventional PISA method tends to provide falsely large RV in patients with eccentric MR and a simple geometric AC of the proximal constraint flow largely eliminates overestimation.

Validation of Global Longitudinal Strain and Strain Rate as Reliable Markers of Right Ventricular Dysfunction: Comparison with Cardiac Magnetic Resonance and Outcome

BACKGROUND: Right ventricular (RV) dysfunction in ischemic cardiomyopathy (ICM) is associated with poor prognosis, but RV assessment by conventional echocardiography remains difficult. We sought to validate RV global longitudinal strain (RVGLS) and global longitudinal strain rate (RVGLSR) against cardiac magnetic resonance (CMR) and outcome in ICM. METHODS: In 57 patients (43 men, 64 +/- 12 years) with ICM who underwent conventional and strain echocardiography and CMR, RVGLS and RVGLSR were measured off-line. RV dysfunction was determined by CMR [RV ejection fraction (RVEF) < 50%]. Patients were followed over 15 +/- 9 months for a composite of death and hospitalization for worsening heart failure. RESULTS: RVGLS showed significant correlations with CMR RVEF (r = -0.797, p < 0.01), RV fractional area change (RVFAC, r = -0.530, p < 0.01), and tricuspid annular plane systolic excursion (TAPSE, r = -0.547, p < 0.01). RVGLSR showed significant correlations between CMR RVEF (r = -0.668, p < 0.01), RVFAC (r = -0.394, p < 0.01), and TAPSE (r = -0.435, p < 0.01). RVGLS and RVGLSR showed significant correlations with pulmonary vascular resistance (r = 0.527 and r = 0.500, p < 0.01, respectively). The best cutoff value of RVGLS for detection of RV dysfunction was -15.4% [areas under the curve (AUC) = 0.955, p < 0.01] with a sensitivity of 81% and specificity 95%. The best cutoff value for RVGLSR was -0.94 s-1 (AUC = 0.871, p < 0.01), sensitivity 72%, specificity 86%. During follow-up, there were 12 adverse events. In Cox-proportional hazard regression analysis, impaired RVGLS [hazard ratio (HR) = 5.46, p = 0.030] and impaired RVGLSR (HR = 3.95, p = 0.044) were associated with adverse clinical outcome. CONCLUSION: Compared with conventional echocardiographic parameters, RVGLS and RVGLSR correlate better with CMR RVEF and outcome.

Daño miocárdico por poliarteritis nodosa / Myocardial damage due to polyarteritis nodosa

La poliarteritis nodosa (PAN) es una enfermedad no granulomatosa que afecta principalmente arterias de mediano calibre, aunque su etiología es desconocida, la lesión predominante involucra neutrófilos y mononucleares, con cambios que ocasionan formación de aneurismas y finalmente oclusión del vaso y necrosis miocárdica. Otros hallazgos en PAN son alteraciones del sistema de conducción e hipertensión arterial sistémica. Hoy, en pocos estudios relacionados con lesión miocárdica por PAN, sólo se describe un estudio realizado en la Clínica Mayo en 1926 donde se estudiaron 66 corazones con esta lesión. Así, en el presente caso se describen los hallazgos por resonancia magnética que anteriormente sólo se describían en estudios de autopsias.

The polyarteritis nodosa (PAN) is nongranulomatous disease of only medium sized arteries, the etiology of medium sized vessel vasculitis compatible with PAN is unknown, instead the predominance of neutrophils and mononuclear cells, with weakening of the vessel wall and aneurysm formation, causing stenosis and occlusion and finally myocardial infarct. Other finding in PAN are conduction system abnormalities and systemic arterial hypertension. There a few knowledge relationed in cardiac damage by PAN, as we can notice in a old study realized in the Mayo Clinic by a review of autopsy records for the period 1926 to 1958 involving cases of PAN, the studies the heart in 66 cases. In this patient we can distinguish fibrosis using late gadolinium enhancement were we found a patchy pattern as old studies showed by autopsy.