Hari P. Chaliki

Determination of left ventricular filling pressure by Doppler echocardiography in patients with coronary artery disease : Critical role of left ventricular systolic function

OBJECTIVES This study was designed to determine the usefulness of transthoracic Doppler measurements in detecting increased left ventricular (LV) end-diastolic pressure in patients with coronary artery disease, specifically examining the influence of systolic function on the accuracy of these methods. BACKGROUND Studies that have correlated Doppler indexes with LV filling pressures primarily involved patients with LV systolic dysfunction. The reliability of Doppler indexes in estimating filling pressures in patients with coronary artery disease and preserved systolic function is unclear. METHODS Pulsed wave Doppler transmitral and pulmonary venous flow velocity curves and LV pressure were recorded in 83 patients with coronary artery disease. RESULTS Conventional Doppler indexes (deceleration time of mitral E wave velocity, ratio of peak mitral E to A wave velocities and pulmonary venous systolic fraction) correlated with LV filling pressure in patients with an ejection fraction (EF) < or = 50% but not in those with an EF > 50%. Previously published regression analysis for prediction of LV filling pressure was accurate in patients with an EF < or = 50% but not in those with an EF > 50%. The difference between flow duration with atrial contraction in the pulmonary veins and transmitral flow duration with atrial contraction correlated with LV filling pressure in both groups. CONCLUSIONS Analysis of the early diastolic portion of the transmitral or pulmonary venous flow velocity curves can be used to predict LV filling pressures in patients with systolic dysfunction, but are inaccurate in patients with preserved systolic function. The combined analysis of both flow velocity curves at atrial contraction is a reliable, feasible predictor of increased LV filling pressure, irrespective of systolic function.

Outcomes After Aortic Valve Replacement in Patients With Severe Aortic Regurgitation and Markedly Reduced Left Ventricular Function

Background—Left ventricular dysfunction is an indication for aortic valve replacement (AVR) in patients with severe aortic regurgitation (AR). However, the postoperative outcome of patients with severe AR and a markedly low ejection fraction (EF) is not known. Methods and Results—The study group consisted of a total of 450 patients who had AVR for isolated AR between 1980 and 1995. Patients with markedly reduced left ventricular function (EF <35%, LoEF, n=43) were compared with those with moderate reduction in left ventricular function (EF 35% to 50%, MedEF, n=134) and those with normal left ventricular function (EF ≥50%, Nl EF, n=273). The operative mortality rate was higher with LoEF (14%) than with MedEF and Nl EF (6.7% and 3.7%, respectively, P =0.02). At 10 years, 41%±9% of LoEF patients had survived compared with 56%±5% and 70%±3% of MedEF and Nl EF patients, respectively (P <0.0001). Congestive heart failure occurred at 10 years in 25%±9% with LoEF compared with 17%±4% and 9%±2% with MedEF and NL EF, respectively (P <0.003). Postoperative EF improved by 4.9%±13.8% in the LoEF group and by 4%±11.9% in the MedEF group compared with −2.3%±10.9% in the Nl EF group (P <0.002 and P <0.0001, respectively). Conclusions—Patients with severe AR and markedly low EF incur excess operative mortality rates, postoperative mortality rates, and congestive heart failure after AVR. However, postoperative EF improves markedly, and most patients enjoy a long postoperative survival without recurrence of heart failure after AVR; thus they should not be denied the benefits of AVR.

Cerebral Ischemic Events Associated With ‘Bubble Study’ for Identification of Right to Left Shunts

Background and Purpose— Detection of an intracardiac shunt is frequently sought during the evaluation of patients with cryptogenic ischemic stroke and agitated saline intravenous injection, or “bubble study” (BS), is performed in most cases. We present the first attempt to identify the clinical features in patients who had cerebral ischemic events with BS. Methods— Using a list serve established by the American Academy of Neurology, a member posted a question regarding the safety of BS in patients with patent foramen ovale. A standardized questionnaire was used to gather data about patients with cerebral ischemic events, details of each case were reviewed, and the findings pooled. Results— Five patients with ischemic complications of BS (all female, aged 42 to 90 years) were identified from 4 institutions, 3 ischemic strokes and 2 transient ischemic attacks. Events occurred either during or within 5 minutes of BS. Early brain MRIs confirmed acute infarction in 3, including one who had transient symptoms. MRI infarct volumes were small, and deficits were mild in those who developed stroke. Diagnostic evaluation revealed a patent foramen ovale alone in one case, a pulmonary arteriovenous malformation in one case, and a patent foramen ovale and/or pulmonary shunt in 3 cases. Conclusions— Ischemic cerebrovascular complications can occur in patients who undergo BS and are associated with the presence of cardiac or pulmonary shunts. The true incidence and degree of disability remains unknown, and further study is indicated to assess the impact of technical differences in BS methodology. Novel methods to promote physician communication such as the use of electronic list serves may reduce barriers to reporting of drug, technique, or device complications and should be explored to identify rare complications that otherwise will likely go unappreciated.

Cardiac risk in patients aged >75 years with asymptomatic, severe aortic stenosis undergoing noncardiac surgery.

Severe aortic stenosis (AS) is a known predictor of cardiac risk during noncardiac surgery. However, for patients with asymptomatic AS, it is unclear whether aortic valve surgery should precede noncardiac surgery. We studied 30 patients with asymptomatic, severe AS with a mean age of 78 + or - 9 years, an aortic valve area of 0.77 + or - 0.16 cm(2), a mean gradient of 50.1 + or - 9.5 mm Hg, and a peak gradient of 84 + or - 22 mm Hg. They were compared to 60 age-matched (within 2 years) and gender-matched (ratio of 1:2) patients with mild-to-moderate AS (controls). The primary end point of the study was a composite of death, myocardial infarction, heart failure, ventricular arrhythmias before dismissal, and intraoperative hypotension requiring vasopressor administration. Most patients (>75%) and controls underwent intermediate-risk surgical procedures that were similar with respect to the nature of the surgery, type of anesthesia used, and preoperative risk assessment. Combined postoperative events were more common for the patients (n = 10; 33%) than for the controls (n = 14; 23%), but the difference was not statistically significant (p = 0.06). Intraoperative hypotension requiring vasopressor use was more likely for the patients (n = 9; 30%) than for the controls (n = 10; 17%; odds ratio 2.5; p = 0.11). The perioperative myocardial infarction rates were similar for both groups (3%; p = 0.74). No deaths, heart failure events, or ventricular arrhythmias occurred in the patients and 1 death and 1 ventricular arrhythmia episode occurred in the controls. In conclusion, intermediate-to-low-risk noncardiac surgery for patients with severe, asymptomatic AS can be performed relatively safely. Intraoperative hypotension was frequent and required prompt and aggressive treatment.

Predictors for the development of severe tricuspid regurgitation with anatomically normal valve in patients with atrial fibrillation.

Background and Aims: Atrial fibrillation (AF) may be a risk factor for severe functional tricuspid valve regurgitation (FTR). We aimed to determine the predictors of severe FTR in patients with AF. Methods and Results: From our echocardiographic laboratory database, we searched for and reviewed the medical records of consecutive patients with severe FTR and AF seen at Mayo Clinic in Arizona from 2002 through 2009. Our search identified 42 patients who met all inclusion criteria. These patients (cases) with severe FTR and AF were compared with 38 patients (controls) with AF who had no greater than mild tricuspid regurgitation. Case patients with severe FTR were older than controls (mean, 81 years vs. 76 years; P < 0.001) and more frequently had chronic AF (69% vs 26%; P < 0.001). Mean right atrial volume (86 mL/m2 vs 46 mL/m2; P < 0.001), right ventricular volume (42 mL ± 33 mL vs 22 mL ±8 mL; P < 0.001) and tricuspid annular diameter (3.6 cm vs 3.0 cm; P < 0.001) were larger in cases than in controls. Patients with severe FTR also had a higher prevalence of right‐sided heart failure (69% vs 16%; P < 0.001). After adjusting for age and gender, right atrial and right ventricular volumes were independent predictors for the development of severe FTR in patients with AF (odds ratio, 1.7 [95% CI, 1.3–2.8] for every 10 mL/m2 increase in right atrial volume; P = 0.0002 and odds ratio, 3.1 [95% CI, 1.5–8.9] for every 10 mL increase in right ventricular volume; P = 0.0002). Conclusions: Severe FTR occurs in older patients with chronic AF as a result of marked right atrial and right ventricular dilatation; and enlargement of the tricuspid annulus in the absence of pulmonary hypertension. More importantly, severe FTR leads to increased prevalence of right‐sided heart failure underscoring the nonbenign nature of chronic AF. (Echocardiography 2012;29:140‐146)

Revisiting the Simplified Bernoulli Equation

Background: The assessment of the severity of aortic valve stenosis is done by either invasive catheterization or non-invasive Doppler Echocardiography in conjunction with the simplified Bernoulli equation. The catheter measurement is generally considered more accurate, but the procedure is also more likely to have dangerous complications. Objective: The focus here is on examining computational fluid dynamics as an alternative method for analyzing the echo data and determining whether it can provide results similar to the catheter measurement. Methods: An in vitro heart model with a rigid orifice is used as a first step in comparing echocardiographic data, which uses the simplified Bernoulli equation, catheterization, and echocardiographic data, which uses computational fluid dynamics (i.e., the Navier-Stokes equations). Results: For a 0.93cm2 orifice, the maximum pressure gradient predicted by either the simplified Bernoulli equation or computational fluid dynamics was not significantly different from the experimental catheter measurement (p > 0.01). For a smaller 0.52cm2 orifice, there was a small but significant difference (p < 0.01) between the simplified Bernoulli equation and the computational fluid dynamics simulation, with the computational fluid dynamics simulation giving better agreement with experimental data for some turbulence models. Conclusion: For this simplified, in vitro system, the use of computational fluid dynamics provides an improvement over the simplified Bernoulli equation with the biggest improvement being seen at higher valvular stenosis levels.

A Simplified, Practical Approach to Assessment of Severity of Mitral Regurgitation by Doppler Color Flow Imaging With Proximal Convergence: Validation With Concomitant Cardiac Catheterization

OBJECTIVE To compare the proximal convergence method for quantification of mitral regurgitation with findings on concomitant left ventriculography. MATERIAL AND METHODS In 41 patients (22 men and 19 women, 63 +/- 13 years of age), mitral regurgitation was evaluated concomitantly by Doppler color flow jet area, proximal convergence method, and left ventriculography. A simplified measurement of the proximal convergence, consisting of the aliasing radius and velocity of the proximal isosurface (r2 x V), was used. RESULTS Angiographic grade correlated well with the proximal convergence method (r2 x V) but had poor correlation with the Doppler color flow jet area method. All patients with a proximal convergence flow rate of less than 10 cm3/s had grade 1 or 2 mitral regurgitation, whereas patients with a proximal convergence flow rate of more than 20 cm3/s had grade 3 or 4 mitral regurgitation. The severity of mitral regurgitation was indeterminate in patients with proximal convergence flow rates from 10 to 20 cm3/s. CONCLUSION Doppler color flow jet area correlates poorly with angiographic grade of mitral regurgitation. A simplified proximal convergence method is useful for separating grade 3 and 4 from grade 1 and 2 mitral regurgitation in most patients. A group of patients with indeterminate severity of mitral regurgitation remains, however, in whom further assessment is necessary.

Q Fever Endocarditis in the United States

Infections due to Coxiella burnetii, the causative organism of Q fever, are extremely rare in North America. Endocarditis due to the organism has an unusual presentation and poses echocardiographic and laboratory challenges in establishing a diagnosis. We describe the presentation and clinical course of a 40-year-old American man with Q fever endocarditis and briefly discuss the salient issues regarding this entity.

Symptomatic pericardial cyst: a case series

Pericardial cysts are most commonly located at the cardiophrenic angle or, rarely, in the posterior or anterior superior mediastinum. The majority of pericardial cysts are asymptomatic and are found incidentally. Symptomatic pericardial cysts present with dyspnoea, chest pain, or persistent cough. We describe four patients with symptomatic pericardial cysts who were treated with either echocardiographically guided percutaneous aspiration or video-assisted thoracoscopic surgery, or both; thoracotomy; or conservative therapy.

Pulmonary venous pressure: Relationship to pulmonary artery, pulmonary wedge, and left atrial pressure in normal, lightly sedated dogs

Because pulmonary venous pressure has never been measured, it is unclear whether pulmonary wedge pressure measures left atrial pressure, as commonly assumed, or pressure more upstream in the pulmonary venous or capillary beds. Fluid‐filled mean pulmonary artery and pulmonary wedge pressure were compared with pulmonary venous and left atrial pressure obtained with high‐fidelity micromanometer catheters in eight lightly sedated dogs over a physiologic range of filling pressures. In all conditions, mean pulmonary wedge pressure was virtually identical (r = 0.99) to mean left atrial pressure (slope = 0.99; intercept = −0.46 mm Hg). At the same time, mean pulmonary venous pressure (17.1 ± 6.5 mm Hg) was intermediate between mean pulmonary artery pressure (20.2 ± 6.2 mm Hg) and mean pulmonary wedge pressure (13.3 ± 6.2 mm Hg; P < 0.0001) or mean left atrial pressure (13.4 ± 6.3 mm Hg; P < 0.0001). These relationships were maintained over normal and increased pressure ranges. As measured by conventional flow‐directed pulmonary catheters, mean pulmonary wedge pressure accurately reflects left atrial pressure in lightly sedated, spontaneously breathing normal dogs. Cathet Cardiovasc Intervent 2002;56:432–438.