Biomedical subjects

Dipan J Shah

Publications and source records attributed to Dipan J Shah.

8 recordsLinked to original sources

PubMed2026

Circulating Biomarkers Related to Mitral Valve Prolapse: Current Evidence and Mechanistic Perspective.

PURPOSE OF REVIEW: Although imaging remains central to diagnosis and risk stratification, circulating biomarkers provide complementary information reflecting myocardial stress, fibrosis, extracellular matrix remodeling, inflammation, and metabolic dysregulation. The purpose of this review is to critically evaluate current and emerging circulating biomarkers in MVP and to assess whether these biomarkers may improve individualized management of this disease. RECENT FINDINGS: Natriuretic peptides are the most validated biomarkers in MVP, consistently predicting adverse outcomes and providing complementary prognostic information that may help inform the timing of surgical intervention, particularly in asymptomatic patients with significant mitral regurgitation. In contrast, evidence supporting fibrosis and inflammation mediators, proteomics, metabolomics, and circulating microRNAs remains emerging. In arrhythmic MVP, no circulating biomarker is currently recommended for routine risk stratification. Future research should prioritize phenotype-specific MVP registries, biomarker-CMR integration, multi-omics profiling, and biomarker-guided interventional trials.

Humans↗

PubMed2006

Improved detection of coronary artery disease by stress perfusion cardiovascular magnetic resonance with the use of delayed enhancement infarction imaging.

OBJECTIVES: We tested a pre-defined visual interpretation algorithm that combines cardiovascular magnetic resonance (CMR) data from perfusion and infarction imaging for the diagnosis of coronary artery disease (CAD). BACKGROUND: Cardiovascular magnetic resonance can assess both myocardial perfusion and infarction with independent techniques in a single session. METHODS: We prospectively enrolled 100 consecutive patients with suspected CAD scheduled for X-ray coronary angiography. Patients had comprehensive clinical evaluation, including Rose angina questionnaire, 12-lead electrocardiography, C-reactive protein, and calculation of Framingham risk. Cardiovascular magnetic resonance included cine, adenosine-stress and rest perfusion-CMR, and delayed enhancement-CMR (DE-CMR) for infarction imaging. Matched stress-rest perfusion defects in the absence of infarction by DE-CMR were considered artifactual. All patients underwent X-ray angiography within 24 h of CMR. RESULTS: Ninety-two patients had complete CMR examinations. Significant CAD (> or =70% stenosis) was found in 37 patients (40%). The combination of perfusion and DE-CMR had a sensitivity, specificity, and accuracy of 89%, 87%, and 88%, respectively, for CAD diagnosis, compared with 84%, 58%, and 68%, respectively, for perfusion-CMR alone. The combination had higher specificity and accuracy (p < 0.0001), owing to incorporating the exceptionally high specificity (98%) of DE-CMR. Receiver operating characteristic curve analysis demonstrated the combination provided better performance than cine, perfusion, or DE-CMR alone. The accuracy was high in single-vessel and multivessel disease and independent of CAD location. Multivariable analysis including standard clinical parameters demonstrated the combination was the strongest independent CAD predictor. CONCLUSIONS: A combined perfusion and infarction CMR examination with a visual interpretation algorithm can accurately diagnose CAD in the clinical setting. The combination is superior to perfusion-CMR alone.

Aged↗

PubMed2005

Technology insight: MRI of the myocardium.

MRI is emerging as the method of choice for the evaluation of a wide variety of cardiovascular disorders. A major advantage of this technique over the other cardiac imaging modalities is the fact that it allows the operator--via special software programs called pulse sequences--to probe a vast array of biological properties while using the same machine. In this review, we provide the reader with a brief overview of the pulse sequence concept and how it enables MRI practitioners to pursue a multifaceted approach to evaluating the myocardium. We discuss how MRI technology makes this imaging method ideally suited to the assessment of cardiac morphology, contractile function, myocardial perfusion and infarction. In addition, we present clinical scenarios in which the performance of multifaceted imaging by MRI can alter clinical decision making.

Coronary Disease↗

PubMed2005

The case of the disappearing myxoma.

We present a case demonstrating the utility of cardiovascular magnetic resonance (CMR) in the diagnosis of a cardiac mass. A 70-year-old female who presented with chest pressure and left sided jaw pain was found to have a cardiac mass on transthoracic and transesophageal echocardiography that was diagnosed as an atrial myxoma. A cardiac magnetic resonance test determined the mass to be more consistent with a thrombus than a myxoma through a stepwise approach using multiple pulse sequences. Thus, unwarranted and potentially risky thoracic surgery was avoided by the incorporation of a systematic evaluation by cardiac MRI.

Aged↗

PubMed2004

Relation between contractile reserve and improvement in left ventricular function with beta-blocker therapy in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Beta blockers improve left ventricular (LV) ejection fraction but patient responses are heterogenous. We investigated the role of contractile reserve (CR) in predicting beta-blocker response in ischemic and nonischemic cardiomyopathy. Resting and low-dose dobutamine echocardiograms were recorded in 32 patients with heart failure (LV ejection fraction <or=35%), 18 with ischemic cardiomyopathy (IC), and 14 with idiopathic dilated cardiomyopathy (IDC). A segment was defined as CR positive (CR+) or negative (CR-) based on response to dobutamine. Patients were then classified as CR+ or CR- based on number of improved segments (IC group) or ejection fraction improvement (IDC group) in response to dobutamine. During follow-up (2, 6, and 14 months after beta-blocker initiation), response was measured by the percent of segments showing improved contractility from baseline, ejection fraction, and wall motion score index. In the IC group, the percent of improved segments was greater at 2 and 6 months in CR+ versus CR- (70% vs 15% and 39% vs 17%, p <0.05), whereas it was greater at all periods in the patients with IDC (36% vs 9% at 2 months, 50% vs 19% at 6 months, and 63% vs 42% at 14 months, p <0.05). Findings for ejection fraction and wall motion score index were similar. Therefore, time course and magnitude of improvement in LV function in patients with heart failure receiving beta blockers are related to CR status. CR predicts a greater early response in IC, whereas it predicts a greater response at all time periods in IDC. However, even patients without CR showed improvement in LV function at 14 months.

Adrenergic beta-Antagonists↗

PubMed2003

Gadolinium cardiovascular magnetic resonance predicts reversible myocardial dysfunction and remodeling in patients with heart failure undergoing beta-blocker therapy.

BACKGROUND: In some patients with heart failure, beta-blockers can improve left ventricular (LV) function and reduce morbidity and mortality. We hypothesized that gadolinium-enhanced cardiovascular magnetic resonance imaging (CMR) can predict reversible myocardial dysfunction and remodeling in heart failure patients treated with beta-blockers. METHODS AND RESULTS: Forty-five patients with chronic heart failure underwent CMR. Contrast imaging using gadolinium was performed to obtain high-resolution spatial maps of myocardial scarring and viability. Cine imaging was performed to assess LV function and morphology and was repeated in 35 patients after 6 months of beta-blockade. Gadolinium CMR demonstrated scarring in 30 of 45 patients (67%). Scarring was found in 100% of patients with ischemic cardiomyopathy (28 of 28) but in only 12% with nonischemic cardiomyopathy (2 of 17). In the 35 patients who were maintained on beta-blockers and had a second study, there was an inverse relation between the extent of scarring at baseline and the likelihood of contractile improvement 6 months later (P<0.001). For instance, contractility improved in 56% (674 of 1207) of regions with no scarring but in only 3% with >75% scarring (8 of 232). Multivariate analysis showed that the amount of dysfunctional but viable myocardium by CMR was an independent predictor of the change in ejection fraction (P=0.01), mean wall motion score (P=0.0007), LV end-diastolic volume index (P=0.007), and LV end-systolic volume index (P< or =0.0001). CONCLUSIONS: For heart failure patients treated with beta-blockers, gadolinium-enhanced CMR predicts the response in LV function and remodeling.

Adrenergic beta-Antagonists↗

PubMed2003

How we perform delayed enhancement imaging.

Recently, numerous studies have demonstrated the effectiveness of a segmented inversion recovery fast gradient echo (seg IR-FGE) sequence for differentiating injured from normal myocardium. This technique for delayed enhancement imaging has been shown to be effective in identifying the presence and extent of myocardial infarction, as well as predicting improvement in contractile function after coronary revascularization. In this article we outline the procedure of delayed enhancement imaging performed at our center, describe the seg IR-FGE sequence in more detail, including our process for choosing sequence settings, review our process of image interpretation, and highlight potential pitfalls (and techniques to overcome them) that we have encountered in our experience with performing the technique in over 1500 patients.

Contrast Media↗

PubMed2002

Evaluation of valvular regurgitation severity using digital acquisition of echocardiographic images.

BACKGROUND: Digital acquisition is a technique for storing echocardiographic data that offers advantages over conventional videotape (VT); however, limited information is available on its accuracy for the evaluation of valvular regurgitation. METHODS: We evaluated 102 patients with at least 1 regurgitant lesion. Data were obtained on VT and in 1 cardiac cycle stored digitally (1C). To assess for incremental improvement with acquisition of multiple cycles, digital images were also acquired with 2 (2C) or 3 cardiac cycles (3C). Both digital and VT images were graded for regurgitant severity as absent, trivial, mild, moderate, or severe. Kappa statistics were used to assess agreement. RESULTS: A total of 171 valvular regurgitant lesions (mild or greater) were evaluated. The overall agreement between 1C and VT images was kappa = 0.61. With multiple cycle acquisition, there was no improvement in agreement (kappa = 0.56 and 0.57 for 2C and 3C, respectively). When subgrouped, the level of agreement between 1C and VT was slightly lower for the aortic valve than for the mitral or tricuspid valves (kappa = 0.49, 0.63, 0.64, respectively). CONCLUSION: The 1C technique has substantial agreement and correlation with standard VT for the evaluation of regurgitant lesions with the use of color flow Doppler. The acquisition of multiple cardiac cycles does not provide incremental improvement over single beat acquisition.

Echocardiography, Doppler, Color↗