Khalid H. Sheikh

Exercise intolerance in patients with heart failure and preserved left ventricular systolic function: Failure of the Frank-Starling mechanism☆

Invasive cardiopulmonary exercise testing was performed in 7 patients who presented with congestive heart failure, normal left ventricular ejection fraction and no significant coronary or valvular heart disease and in 10 age-matched normal subjects. Compared with the normal subjects, patients demonstrates severe exercise intolerance with a 48% reduction in peak oxygen consumption (11.6 +/- 4.0 versus 22.7 +/- 6.1 ml/kg per min; p less than 0.001), primarily due to a 41% reduction in peak cardiac index (4.2 +/- 1.4 versus 7.1 +/- 1.1 liters/min per m2; p less than 0.001). In patients compared with normal subjects, peak left ventricular stroke volume index (34 +/- 9 versus 46 +/- 7 ml/min per m2; p less than 0.01) and end-diastolic volume index (56 +/- 14 versus 68 +/- 12 ml/min per m2; p less than 0.08) were reduced, whereas peak ejection fraction and end-systolic volume index were not different. In patients, the change in end-diastolic volume index during exercise correlated strongly with the change in stroke volume index (r = 0.97; p less than 0.0001) and cardiac index (r = 0.80; p less than 0.03). Pulmonary wedge pressure was markedly increased at peak exercise in patients compared with normal subjects (25.7 +/- 9.1 versus 7.1 +/- 4.4 mm Hg; p less than 0.0001). Patients demonstrated a shift of the left ventricular end-diastolic pressure-volume relation upward and to the left at rest. Increases in left ventricular filling pressure during exercise were not accompanied by increases in end-diastolic volume, indicating a limitation to left ventricular filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related alterations of Doppler left ventricular filling indexes in normal subjects are independent of left ventricular mass, heart rate, contractility and loading conditions☆☆☆

The purpose of this study was to determine whether age-related alterations in Doppler diastolic filling indexes occur independent of cardiovascular disease and confounding physiologic variables. Ten old (62 to 73 years) and 10 young (21 to 32 years) healthy male volunteers were rigorously screened for cardiovascular disease and underwent comprehensive Doppler echocardiography, radionuclide ventriculography and invasive measurements of right heart and left atrial pressures. There were no differences between the two groups in the physiologic variables of left ventricular mass, volumes, ejection fraction, end-systolic wall stress, left atrial size, heart rate and right atrial, pulmonary artery, pulmonary capillary wedge and systemic arterial pressures. However, there were marked differences in Doppler left ventricular filling indexes. Compared with the young group, the old group had reduced peak early diastolic flow velocity (56 +/- 13 vs. 82 +/- 12 cm/s, p = 0.0002) and increased atrial diastolic flow velocity (59 +/- 14 vs. 43 +/- 10 cm/s, p = 0.009) and had a peak atrial/early flow velocity (A/E) ratio twice that of the young group (1.09 +/- 0.29 vs. 0.54 +/- 0.15, p less than 0.0001). Similar results were obtained for the time-velocity integrals of the peaks. Subjects in the old group also had a markedly reduced peak filling rate (274 +/- 62 vs. 448 +/- 152 ml/s, p = 0.004). In univariate and multivariate regression analyses, peak early and atrial flow velocities were not related to any of the physiologic variables measured once age was accounted for, although peak filling rate, a volumetric measure flow, was related to body surface area as well as age.(ABSTRACT TRUNCATED AT 250 WORDS)

The utility of transesophageal echocardiography and Doppler color flow imaging in patients undergoing cardiac valve surgery

To assess the value of intraoperative transesophageal echocardiography during cardiac valve surgery, 154 consecutive patients who had a valve operation in conjunction with pre- and postcardiopulmonary bypass transesophageal imaging were studied. Prebypass imaging yielded unsuspected findings that either assisted or changed the planned operation in 29 (19%) of the 154 patients. Imaging immediately after bypass revealed unsatisfactory operative results that necessitated immediate further surgery in 10 (6%) of the 154 patients. Postbypass left ventricular dysfunction, prompting administration of inotropic agents, was identified in 13 patients (8%). Transesophageal echocardiography proved most useful when both two-dimensional and Doppler color flow imaging were employed in patients undergoing a mitral valve operation, where surgical decisions based on echocardiographic results were made in 26 (41%) of 64 cases. Postbypass echocardiographic findings identified patients at risk for an adverse postoperative outcome. Of 123 patients whose postbypass valve function was judged to be satisfactory, 18 (15%) had a major postoperative complication and 6 (5%) died, whereas of 7 patients with moderate residual valve dysfunction, 6 (86%) had a postoperative complication and 3 (43%) died (p less than 0.05 for both). Likewise, of 131 patients with preserved postbypass left ventricular function, 12 (9%) had a major complication and 7 (5%) died, whereas of 23 patients with reduced ventricular function, 17 (73%) had a postoperative complication and 6 (26%) died (p less than 0.05 for both). These data indicate that intraoperative transesophageal echocardiography is useful in formulating the surgical plan, assessing immediate operative results and identifying patients with unsatisfactory results who are at increased risk for postoperative complications.

Real-Time, Three-Dimensional Echocardiography: Feasibility and Initial Us

The purpose of this article is to review new approaches to three‐dimensional acquisition and presentation ofechocardiographic data. New three‐dimensional phased‐array devices hold great promise for the development and application of new descriptors for left ventricular performance, myocardial perfusion, and other important indices of cardiac function. (ECHOCARDIOGRAPHY, Volume 8, January 1991)

Intraoperative transesophageal Doppler color flow imaging used to guide patient selection and operative treatment of ischemic mitral regurgitation.

BackgroundIntraoperative transesophageal Doppler color flow imaging (TDCF) affords the opportunity to assess mitral valve competency immediately before and after cardiopulmonary bypass (CPB). The purpose of this study was to assess the utility of TDCF to assist in the selection and operative treatment of ischemic mitral regurgitation (MR). Methods and ResultsTwo hundred forty-six patients undergoing surgery for ischemic heart disease were prospectively studied. All had preoperative cardiac catheterization. Catheterization and pre-CPB TDCF were discordant in their estimation of MR in 112 patients (46%). Compared with patients in whom both techniques agreed in estimation of MR, patients with discordance in MR were more likely to have had unstable clinical syndromes at the time of catheterization (79% versus 40%, p < 0.05) or to have received thrombolytics (16% versus 8%, p < 0.05). Pre-CPB TDCF resulted in a change in the operative plan with respect to the mitral valve in 27 patients (11%). Because less MR was found by TDCF than catheterization, 22 patients had only coronary bypass grafting when combined coronary bypass and mitral valve surgery had been planned. Because more MR was found by TDCF than catheterization, five patients had combined coronary bypass and mitral valve surgery when coronary bypass alone had been planned. Unsatisfactory results noted by TDCF following mitral valve surgery in five patients resulted in immediate corrective surgery. Cox regression analysis identified residual MR at the completion of surgery to be an important predictor of survival (X2=21.4) after surgery-more important than patient age (X2=8.3) or left ventricular ejection fraction (x2=5.3). ConclusionsThese results indicate that TDCF is useful in guiding patient selection and operative treatment of ischemic MR and that in such patients, intraoperative TDCF should be performed routinely.

Relation of quantitative coronary lesion measurements to the development of exercise-induced ischemia assessed by exercise echocardiography

To assess the relation of quantitative measures of coronary stenoses to the development of exercise-induced regional wall motion abnormalities, 34 patients with isolated, single vessel coronary artery lesions and normal wall motion at rest underwent exercise echocardiography and quantitative angiography on the same day. Although all 11 patients with a visually estimated stenosis greater than or equal to 75% had an ischemic response and 10 (91%) of 11 patients with a less than or equal to 25% visually estimated stenosis had a normal response by exercise echocardiography, among 12 patients with a visually estimated stenosis of 50%, 6 (50%) had an ischemic response and 6 (50%) had a normal exercise echocardiogram. Quantitative measurements of stenosis severity distinguished patients with ischemic (group 1) from normal (group 2) exercise echocardiographic responses as follows: minimal luminal diameter (mm), group 1 1.0 +/- 0.4 versus group 2 1.7 +/- 0.4, p less than 0.0001; minimal cross-sectional area (mm2), group 1 0.9 +/- 0.6 versus group 2 2.5 +/- 1.1, p less than 0.0001; percent diameter stenosis, group 1 68.3 +/- 14.2 versus group 2 42.2 +/- 12.1, p less than 0.0001; and percent area stenosis, group 1 87.5 +/- 7.8 versus group 2 64.8 +/- 15.9, p less than 0.0001. These data validate the utility of exercise echocardiography by demonstrating that 1) coronary stenosis severity measured by quantitative angiography is closely related to wall motion abnormalities detected by exercise echocardiography, and 2) exercise echocardiography can be used as a noninvasive means to assess the physiologic significance of coronary artery lesions.

Intracoronary ultrasound evaluation of interventional technologies.

The feasibility and applicability of intravascular ultrasound (IVUS) of the coronary arteries were evaluated in 65 patients undergoing 70 coronary interventional procedures. Morphologic and quantitative analyses were performed with a mechanically rotated IVUS catheter (4.8Fr, 20 MHz) and with orthogonal view cineangiography. A semiautomated edge-detection algorithm was used for cineangiographic quantification. Coronary interventions included 45 percutaneous transluminal coronary angioplasties, 9 excimer lasers, 11 directional coronary atherectomies, 3 rotational atherectomies and 2 stents. Most lesions consisted of a mixture of plaque composition (hard, n = 30; soft, n = 64). Other unique morphologic data by IVUS were plaque topography (eccentric, n = 34; concentric, n = 36) and vessel dissection (IVUS [n = 29] versus angiography [n = 14], p less than 0.05). Postprocedure minimal lumen diameter and cross-sectional area measured by IVUS were larger and poorly correlated with angiography (r = 0.28, standard error of the estimate = 0.52 mm; r = 0.08, standard error of the estimate = 1.0 cm2, respectively). IVUS is more sensitive than angiography when assessing postintervention lesion characteristics including vessel dissection and plaque morphology. Catheter-based ultrasound appears to be a useful adjunct to contrast angiography when evaluating and comparing the therapeutic impact of conventional percutaneous transluminal coronary angioplasty with new technologies.

Utility of Doppler color flow imaging for identification of femoral arterial complications of cardiac catheterization

Doppler color flow and two-dimensional ultrasonographic images of the femoral region were obtained in 25 patients referred for suspected vascular complications of cardiac catheterization. Five patients had normal findings, while 23 abnormalities were noted in 20 patients, including seven femoral arteriovenous fistulae, 12 femoral pseudoaneurysms, and two patients with both femoral arteriovenous fistulas and pseudoaneurysms. Operation confirmed the abnormalities diagnosed by color flow examination in 15 of 20 patients. Three patients refused operation and one was not felt to be a surgical candidate due to high anesthetic risk. One patient died preoperatively and postmortem examination confirmed the color flow diagnosis. Etiologies of the arterial complications included percutaneous aortic valvuloplasty (6), coronary angioplasty (4), and arterial or both arterial and venous catheterization (10). Doppler color flow imaging is a reliable technique for identification of vascular complications following catheterization procedures.

The use of intraoperative echo with Doppler color flow imaging to predict outcome after repair of congenital cardiac defects.

Surgical repair of congenital cardiac defects (CCD) has undergone a remarkable evolution in the past decade. Major defects are now often completely corrected in early infancy with continually improving rates of survival. It has become clear that the next major focus will be improvements in the long-term quality of life and this has promoted many innovations in surgical technique and approach. One advance is the use of intraoperative echo with Doppler color flow imaging (echo-DCFI) to evaluate the exactness of operative repair. Aside from anecdotal reports, very little information is available regarding the interpretation of images produced by this technology in the operating room. Furthermore there have been no studies addressing the predictive value of intraoperative echo-DCFI findings with respect to outcome for patients undergoing repair of CCD. The prospective data obtained by following the course of 273 patients receiving intraoperative echo-DCFI has been reviewed after repair of a variety of CCD (age range, 1 to 53 years; mean 5.3 years; smallest patient, 1.8 kg). Forty-seven patients (17%) had initially unacceptable results, by echo, at the completion of their repair. Eighteen of these patients (7% of entire series) had no clinical problems and the defects were discernible only by echo. Twenty-six patients with initially unacceptable results had their repairs revised in the operating room and left with an acceptable result by echo. Twenty-one patients were allowed to leave the operating room with echo-discernible defects. Follow-up of these patients demonstrated a significantly higher (p less than 0.006) rate of reoperation (42% vs. 3%) and of early death (29% vs. 10%) for those patients whose defects were left unrepaired compared to those whose problems were corrected before leaving the operating room. Sixty-eight patients (25%) had some alteration of ventricular function (compared to their prebypass evaluation) at the completion of their repair. Regardless of whether the dysfunction was limited to the right ventricle, left ventricle, or was biventricular, patients in this group had a significantly higher incidence (p less than 0.004) of early, but not late, death compared to patients without alteration of ventricular function (35% vs. 4%). Patients who left the operating room with no problems of concern by echo-DCFI had a greater than 90% likelihood of a long-term acceptable outcome compared to patients who had any problem of concern (residual defect, anatomic or technical imperfection, ventricular dysfunction, and so on) whose long-term likelihood of an acceptable outcome approached 50% (p less than 0.0125).(ABSTRACT TRUNCATED AT 400 WORDS)

Balloon angioplasty of coarctation of the aorta evaluated with intravascular ultrasound imaging

Intravascular ultrasound images were employed to evaluate aortic coarctation before and after balloon angioplasty. Measurements obtained with use of an ultrasound imaging catheter correlated well with measurements made with digital aortography, both in the area of coarctation and in areas proximal and distal to it. The intravascular ultrasound images dramatically revealed dissection of the aortic wall and an intimal flap that was not appreciated on cineaortography or digital subtraction angiography. Intravascular ultrasound imaging may yield important morphologic information unavailable by other imaging techniques. Such information may allow more precise definition of the results of intravascular procedures and improve understanding of lesion characteristics predictive of a successful outcome.