The role of tissue Doppler imaging in predicting left ventricular filling pressures in patients undergoing cardiac surgery: an intraoperative study.

INTRODUCTION: The perioperative management of patients undergoing cardiac surgery usually requires the accurate assessment of left ventricular filling pressures (LVFP). The gold standard for determining LVFP involves the use of pulmonary artery catheters (PAC). Using tissue Doppler indices (TDI) obtained by transthoracic echocardiography, the ratio of early transmitral filling velocity to the corresponding early mitral annular velocity (E/E') has a strong correlation with pulmonary capillary wedge pressure (PCWP). Little is known, however, on whether this relationship between E/E' and PCWP is valid intraoperatively using transesophageal echocardiography (TEE) during cardiac surgery. OBJECTIVE: The objective of our study was to determine whether TDI obtained by intraoperative TEE during cardiac surgery can accurately estimate PCWP using PAC as the gold standard. METHODS AND RESULTS: A total of 34 patients (26 males, mean age 64 ± 9 years) undergoing cardiac surgery were prospectively enrolled between 2010 and 2011 at a single tertiary care center. Conventional diastolic and tissue Doppler parameters were evaluated using intraoperative TEE with concurrent PAC monitoring before and after cardiopulmonary bypass (CPB) surgery. At both pre- and post-CPB, there was no significant correlation between lateral, septal, and mean E/E' obtained by TEE and PCWP. CONCLUSION: Intraoperative TEE was unable to accurately predict LVFP in patients undergoing cardiac surgery. PAC may continue to be the gold standard in the assessment of LVFP for this patient population.

The impact of repeated marathon running on cardiovascular function in the aging population.

BACKGROUND: Several studies have correlated elevations in cardiac biomarkers of injury post marathon with transient and reversible right ventricular (RV) systolic dysfunction as assessed by both transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR). Whether or not permanent myocardial injury occurs due to repeated marathon running in the aging population remains controversial. OBJECTIVES: To assess the extent and severity of cardiac dysfunction after the completion of full marathon running in individuals greater than 50 years of age using cardiac biomarkers, TTE, cardiac computed tomography (CCT), and CMR. METHODS: A total of 25 healthy volunteers (21 males, 55 ± 4 years old) from the 2010 and 2011 Manitoba Full Marathons (26.2 miles) were included in the study. Cardiac biomarkers and TTE were performed one week prior to the marathon, immediately after completing the race and at one-week follow-up. CMR was performed at baseline and within 24 hours of completion of the marathon, followed by CCT within 3 months of the marathon. RESULTS: All participants demonstrated an elevated cTnT post marathon. Right atrial and ventricular volumes increased, while RV systolic function decreased significantly immediately post marathon, returning to baseline values one week later. Of the entire study population, only two individuals demonstrated late gadolinium enhancement of the subendocardium in the anterior wall of the left ventricle, with evidence of stenosis of the left anterior descending artery on CCT. CONCLUSIONS: Marathon running in individuals over the age of 50 is associated with a transient, yet reversible increase in cardiac biomarkers and RV systolic dysfunction. The presence of myocardial fibrosis in older marathon athletes is infrequent, but when present, may be due to underlying occult coronary artery disease.

Multimodality imaging of aortic dimensions: comparison of transthoracic echocardiography with multidetector row computed tomography.

BACKGROUND: With recent advances in multimodality cardiac imaging, a number of methods exist for the noninvasive assessment of aortic disease. Although multidetector row computed tomography (MDCT) remains the gold standard for aortic measurements, there are a number of limitations including radiation and contrast-induced nephropathy. Transthoracic echocardiography (TTE) is an alternative to MDCT for providing accurate anatomic assessment of aortic root and ascending aorta dimensions. OBJECTIVES AND METHODS: To determine the accuracy of two-dimensional (2D) TTE for determining aortic measurements in comparison to MDCT, a retrospective study of individuals with varying aortic root and ascending aorta dimensions was performed. RESULTS: There were 116 patients (77 males, mean age 49 ± 12 years) in total. The maximum aortic diameters by 2D TTE were 26.1 ± 4.3 mm (annulus), 32.4 ± 5.6 mm (sinuses), 30.1 ± 5.9 mm (sinotubular [ST] junction), and 33.4 ± 7.3 mm (ascending aorta). The maximum aortic diameters by MDCT were 30.1 ± 4.1 mm (annulus), 35.8 ± 5.8 mm (sinuses), 33.2 ± 5.9 mm (ST junction), and 37.4 ± 7.6 mm (ascending aorta). There was good to excellent correlation between 2D TTE and MDCT at all four levels of the aorta (annulus: r = 0.84; sinuses: r = 0.93; ST junction: r = 0.93; ascending aorta: r = 0.88). There was a consistent underestimation of aortic measurements obtained by 2D TTE when compared to MDCT. CONCLUSION: 2DTTE is a feasible, accurate, and reproducible method for the noninvasive assessment of thoracic aortic diameters as compared to MDCT.

Obstructive sleep apnea: effects of continuous positive airway pressure on cardiac remodeling as assessed by cardiac biomarkers, echocardiography, and cardiac MRI.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with an increased risk of cardiovascular morbidity and mortality. Although previous echocardiographic studies have demonstrated short-term improvement in cardiovascular remodeling in patients with OSA receiving continuous positive airway pressure (CPAP) therapy, a long-term study incorporating cardiac biomarkers, echocardiography, and cardiac MRI (CMR) has not been performed to date. METHODS: A prospective study of 47 patients with OSA was performed between 2007 and 2010. Cardiac biomarkers, including C-reactive protein (CRP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and troponin T (TnT), were measured at baseline and serially over 1 year. All patients underwent baseline and serial transthoracic echocardiography (TTE) and CMR to assess cardiac remodeling. RESULTS: Following 12 months of CPAP therapy, levels of CRP, NT-proBNP, and TnT did not change significantly from normal baseline values. As early as 3 months after initiation of CPAP, TTE revealed an improvement in right ventricular end-diastolic diameter, left atrial volume index, right atrial volume index, and degree of pulmonary hypertension, which continued to improve over 1 year of follow-up. Finally, left ventricular mass, as determined by CMR, decreased from 159 ± 12 g/m(2) to 141 ± 8 g/m(2) as early as 6 months into CPAP therapy and continued to improve until completion of the study at 1 year. CONCLUSION: Both systolic and diastolic abnormalities in patients with OSA can be reversed as early as 3 months into CPAP therapy, with progressive improvement in cardiovascular remodeling over 1 year as assessed by both TTE and CMR.

The utility of cardiac biomarkers, tissue velocity and strain imaging, and cardiac magnetic resonance imaging in predicting early left ventricular dysfunction in patients with human epidermal growth factor receptor II-positive breast cancer treated with adjuvant trastuzumab therapy.

OBJECTIVES: The aim of this study was to evaluate whether cardiac biomarkers, tissue velocity (TVI) and strain imaging, and cardiac magnetic resonance imaging can predict early left ventricular (LV) dysfunction in human epidermal growth factor receptor II-positive breast cancer patients treated with trastuzumab in the adjuvant setting. BACKGROUND: Early indexes of LV systolic dysfunction with noninvasive cardiac imaging would be useful for addressing the cardiac safety profile of trastuzumab, potentially avoiding the detrimental effects of heart failure. METHODS: We used cardiac biomarkers, TVI and strain imaging, and cardiac magnetic resonance imaging to detect pre-clinical changes in LV systolic function, before conventional changes in left ventricular ejection fraction (LVEF) in human epidermal growth factor receptor II-positive breast cancer patients treated with trastuzumab in the adjuvant setting. RESULTS: Of 42 patients (mean age 47 ± 9 years) prospectively followed between 2007 and 2009, 10 (25%) developed trastuzumab-mediated cardiomyopathy (CM). Troponin T, C-reactive protein, and brain natriuretic peptide did not change over time. Within 3 months of adjuvant therapy with trastuzumab, there was a significant difference in the lateral S' between the normal cohort and the CM group (9.1 ± 1.6 cm/s and 6.4 ± 0.6 cm/s, respectively, p < 0.05). Similarly, the peak global longitudinal and radial strain decreased as early as 3 months in the trastuzumab-mediated cardiotoxicity group. As compared with both global longitudinal and radial strain, only S' was able to identify all 10 patients who developed trastuzumab-mediated CM. The LVEF subsequently decreased at 6 months of follow-up in all 10 patients, necessitating discontinuation of the drug. All 10 patients demonstrated delayed enhancement of the lateral wall of the LV within the mid-myocardial portion, consistent with trastuzumab-induced CM. CONCLUSIONS: Both TVI and strain imaging were able to detect pre-clinical changes in LV systolic function, before conventional changes in LVEF, in patients receiving trastuzumab in the adjuvant setting.

The cardioprotective role of probucol against anthracycline and trastuzumab-mediated cardiotoxicity.

OBJECTIVE: Although the combination of doxorubicin (Dox) and trastuzumab (Trz) reduces breast cancer progression and recurrence, it is limited by significant cardiotoxic side effects. Little is known about the utility of antioxidants in the prevention of this drug-induced cardiomyopathy. The aim of the study was to determine whether the antioxidant probucol (Prob) would be useful in attenuating Dox and Trz-mediated cardiotoxicity. METHODS: A total of 114 mice were randomized to treatment with Trz, Dox, or Dox+Trz. Within each arm, mice received prophylactic treatment with placebo or Prob. Serial murine echocardiography with tissue Doppler imaging was performed daily for 10 days. At 10 days posttreatment, the hearts were removed for histopathologic and Western blot analyses. RESULTS: Left ventricular cavity dimensions and systolic parameters were preserved in mice prophylactically treated with Prob after the administration of Dox+Trz. Although the combination of Dox+Trz demonstrated >80% mortality at day 5, prophylactic treatment with Prob reduced mortality to 40% at day 10. There was decreased histologic evidence of cardiac damage and reduced apoptosis due to Dox+Trz in mice pretreated with Prob. CONCLUSION: The cardiotoxic effects of Dox+Trz are partially attenuated by the prophylactic administration of the antioxidant Prob.

An unusual presentation of left ventricular free wall rupture.

Left ventricular free wall rupture (LVFWR) is one of the most lethal complications following myocardial infarction. It accounts for approximately 12% to 21% of all in-hospital deaths following myocardial infarction. The majority of patients die shortly after LVFWR from instantaneous pericardial tamponade and hemodynamic collapse. However, up to one-third of cases are subacute in nature, allowing limited time for emergent surgical repair to prevent sudden death. A high index of suspicion and timely use of diagnostic tests are important in recognizing cases. The present report describes the case of a 69-year-old man who initially presented with acute pericardial tamponade and was subsequently diagnosed with LVFWR in the operating room as the cause of his hemopericardium. The pathology, diagnosis and management of LVFWR are reviewed.

The utility of dobutamine stress echocardiography for the diagnosis of coronary artery disease in the HIV population.

BACKGROUND: The introduction of highly active antiretroviral therapy (HAART) has increased human immunodeficiency virus (HIV) patient longevity by 10-15 years. This increased longevity has habituated new cardiovascular complications, in particular, accelerated coronary artery disease (CAD). Although dobutamine stress echocardiography (DSE) is a highly sensitive and specific test for the noninvasive detection of underlying CAD in the general population, its utility in the HIV population remains unknown. OBJECTIVE: The objective of the current study was to assess the validity of DSE for the noninvasive detection of underlying symptomatic CAD in the HIV population using cardiac catheterization as the gold standard. METHODS AND RESULTS: A total of 40 HIV positive patients (mean 49 ± 8 years; 31 males) between 2006 and 2009 inclusively underwent routine DSE and coronary angiography. A positive stress echo with new wall motion abnormalities was detected in 9 (23%) individuals. Coronary angiography, following DSE, detected obstructive CAD in 12 (30%) individuals. For the diagnosis of obstructive CAD, DSE has a sensitivity of 67%, specificity of 97%, positive predictive value (PPV) of 89%, and negative predictive value (NPV) of 87%. CONCLUSION: In this select HIV population, DSE was highly specific for the noninvasive detection of obstructive CAD.