The influence of clinical risk factors on pre-operative B-type natriuretic peptide risk stratification of vascular surgical patients.

The role of the revised cardiac risk index in risk stratification has recently been challenged by studies reporting on the superior predictive ability of pre-operative B-type natriuretic peptides. We found that in 850 vascular surgical patients initially risk stratified using B-type natriuretic peptides, reclassification with the number of revised cardiac risk index risk factors worsened risk stratification (p < 0.05 for > 0, > 2, > 3 and > 4 risk factors, and p = 0.23 for > 1 risk factor). When evaluated with pre-operative B-type natriuretic peptides, none of the revised cardiac risk index risk factors were independent predictors of major adverse cardiac events in vascular patients. The only independent predictor was B-type natriuretic peptide stratification (OR 5.1, 95% CI 1.8-15 for the intermediate class, and OR 25, 95% CI 8.7-70 for the high-risk class). The clinical risk factors in the revised cardiac risk index cannot improve a risk stratification model based on B-type natriuretic peptides.

Four-year prospective study of pulmonary venous thrombosis after lung transplantation.

The objective of this study was to prospectively assess pulmonary venous anastomosis by transesophageal echocardiography after lung transplantation. Thrombus formation at the pulmonary venous anastomotic site after lung transplantation may have catastrophic consequences, including allograft failure and stroke. Eighty-seven consecutive adult lung transplant recipients underwent transesophageal echocardiography within 48 hours after surgery. Thrombosis of a pulmonary vein was diagnosed in 13 (15%) of 87 patients in the early postoperative period after lung transplantation. Mean thrombus width was 0.9 +/- 0.4 cm (range, 0.5 to 1.7 cm), with an average peak flow velocity at the site of obstruction of 127 +/- 23 cm/s (range, 90 to 150 cm/s). Five patients with pulmonary vein thrombosis died in the perioperative period, yielding a 90-day mortality rate of 38%. Larger thrombus size and greater acceleration of flow through a narrowed pulmonary vein correlated with poor clinical outcome. During each year of the study, the incidence of pulmonary vein thrombosis declined progressively. Pulmonary vein thrombosis is a potentially ominous complication in the early postoperative period after lung transplantation. Transesophageal echocardiography is a valuable tool for detecting abnormalities of the pulmonary venous anastomosis. Thrombus size and flow velocity at the anastomotic site may guide prognosis and clinical management. Complications of the pulmonary venous anastomosis are in part technical in nature.

Transvenous pacemaker leads do not worsen tricuspid regurgitation: a prospective echocardiographic study.

Limited prospective data are available regarding the influence of pacemaker leads on tricuspid valve function. To examine the true incidence of these complications, 35 patients were prospectively examined by two-dimensional and Doppler echocardiography before and after implantation of either a permanent pacemaker or an automatic implantable cardioverter-defibrillator. Of the 35 patients imaged preoperatively, the amount of tricuspid regurgitation (TR) was judged as normal or trivial in 15 (43%), mild in 10 (29%), moderate in 8 (23%), and severe in 2 (6%). Following electrode implantation, TR was noted to be normal or trivial in 13 (38%), mild in 15 (48%), moderate in 6 (17%) and severe in 1 (3%). We conclude that implantation of permanent right ventricular electrodes is not usually associated with an acute worsening of tricuspid regurgitation in most patients.

Association between right ventricular function and perfusion abnormalities in hemodynamically stable patients with acute pulmonary embolism.

BACKGROUND/OBJECTIVES: Patients presenting with acute pulmonary embolism associated with hemodynamic compromise exhibit right ventricular enlargement and dysfunction on transthoracic echocardiogram. However, the degree of echocardiographic abnormalities among hemodynamically stable patients without preexisting cardiopulmonary disease during the acute stage of pulmonary embolism, and following treatment, is unknown. Therefore, this study was designed to assess the extent of right ventricular abnormalities detected on transthoracic echocardiogram in patients following acute pulmonary embolism and during treatment with anticoagulation or vena caval interruption. The extent of pulmonary vascular obstruction and complication rate on follow-up were also assessed. DESIGN/INTERVENTIONS: Sixty-four consecutive hemodynamically stable patients without preexisting known cardiopulmonary disorder presenting with acute pulmonary embolism and undergoing treatment with anticoagulation or inferior vena caval interruption were studied. All subjects underwent a two-dimensional transthoracic echocardiogram within 24 h of diagnosis. The degree of perfusion abnormality on lung scan was quantified. Twenty-six patients underwent follow-up echocardiogram and lung scan at 6 weeks. The echocardiographic findings were compared with those obtained from a group of normal control subjects matched for gender and age. RESULTS: Although the mean right ventricular end-diastolic areas did not differ (21.9+/-5.2 cm2 vs 20.1+/-2.9 cm2 for control subjects; p=not significant), the right ventricular end-systolic area was larger in comparison to our series of control subjects (14.6+/-5.1 cm2 vs 11.7+/-2.0 cm2; p=0.025). Fractional right ventricular area change was reduced in the patient group compared with the control subjects (34.3+/-9.0% vs 41.3+/-7.0%; p=0.003). The extent of right ventricular end-systolic area enlargement and decrease in fractional area change did not correlate with the degree of pulmonary vascular obstruction. Patients who were restudied at 6 weeks showed minimal improvement in echocardiographic findings, despite almost complete resolution of perfusion defects on lung scan. CONCLUSIONS: The extent of right ventricular dysfunction in hemodynamically stable, previously normal patients with acute pulmonary embolism does not reflect the extent of the perfusion abnormalities. Further, right ventricular enlargement and systolic dysfunction are present and persistent despite treatment with heparin and warfarin therapy or vena caval interruption.

Relation between patent foramen ovale and perfusion abnormalities in acute pulmonary embolism.

The frequency of right-to-left shunt through a patent foramen ovale is increased in hemodynamically stable patients without preexisting cardiopulmonary disease with acute pulmonary embolism. This is associated with a greater degree of perfusion abnormalities as quantified by perfusion scan and the presence of tricuspid regurgitation.

Variability of right ventricular functional recovery after lung transplantation.

BACKGROUND: The purpose of this study was to assess by echocardiography the effects of lung transplantation on recovery of right ventricular (RV) function in patients with preoperative RV dysfunction. METHODS: Fourteen (20%) of 71 lung transplant recipients were identified by echocardiography as manifesting abnormal RV function before lung transplantation. These 14 patients were selected for follow-up echocardiographic study 8 months after transplantation. RESULTS: RV function improved significantly in the study group. Mean RV end-diastolic area decreased from 26.8 +/- 7.9 cm2 to 20.1 +/- 4.7 cm2 (P < 0.01); mean RV end-systolic area decreased from 21.5 +/- 6.8 cm2 to 13.1 +/- 4.2 (P < 0.01); and mean RV fractional area change (FAC) increased from 20.4 +/- 3.3% to 35.8 +/- 8.9% (P < 0.001). A subgroup of four patients, however, exhibited no change in RV function. Patients who achieved improvement in RV function tended to be younger, had shorter duration of disease before transplantation, and had higher pulmonary arterial (PA) pressures before transplantation (PA systolic, 89 +/- 28 mmHg vs. 38 +/- 11 mmHg, P < 0.001; PA diastolic, 42 +/- 11 mmHg vs. 19 +/- 3 mmHg, P < 0.002). Each of the eight patients with primary pulmonary hypertension exhibited improvement in RV function (mean delta FAC +20.6 +/- 5.9%), while two of three patients with emphysema and both patients with idiopathic pulmonary fibrosis failed to achieve improvement in RV function (mean delta FAC +2.3 +/- 1.2%). CONCLUSIONS: Improvement of RV function assessed by echocardiography occurs after lung transplantation, even in patients with severe preoperative RV dysfunction. However, the degree of improvement is variable and may depend on the degree of RV after-load reduction and the presence or absence of intrinsic myocardial disease. RV ejection parameters do not distinguish between these two possibilities.

Assessment of cardiac function by three-dimensional echocardiography compared with conventional noninvasive methods.

BACKGROUND: Reliable, serial, noninvasive quantitative estimation of left ventricular ejection fraction is essential for selecting and timing therapeutic interventions in patients with heart disease. Equilibrium radionuclide angiography is widely used for this purpose but has well-recognized limitations. Advantages of echocardiography over equilibrium radionuclide angiography include assessment of wall motion, valvular pathology, and cardiac hemodynamics, in addition to portability, lack of radiation exposure, and substantially lower cost. However, conventional echocardiographic techniques are limited by geometric assumptions, image positioning errors, and use of subjective visual methods. To overcome these limitations, a three-dimensional echocardiographic method was developed. This study compares ejection fraction by three-dimensional echocardiography, quantitative two-dimensional echocardiography, and subjective two-dimensional echocardiographic visual estimation with that by equilibrium radionuclide angiography. METHODS AND RESULTS: Fifty-one unselected patients with suspected heart disease underwent left ventricular ejection fraction determination by equilibrium radionuclide angiography and three-dimensional echocardiography using an interactive line-of-intersection display and a new algorithm, ventricular surface reconstruction, for volume computation. In 44 patients, ejection fractions were also estimated visually by experienced observers from two-dimensional echocardiography and by quantitative two-dimensional echocardiography using an apical biplane summation-of-disks algorithm. An excellent correlation was obtained between three-dimensional echocardiography and equilibrium radionuclide angiography (r = .94 to .97, SEE = 3.64% to 5.35%; limits of agreement, 10.3% to 13.3%) without significant underestimation or overestimation. SEE values and limits of agreement were twofold to threefold lower than corresponding values for all two-dimensional echocardiographic techniques. In addition, interobserver variability was significantly lower for the three-dimensional echocardiographic method (10.2%) than for the apical biplane summation-of-disks method (26.1%) and subjective visual estimation (33.3%). CONCLUSIONS: Determination of ejection fraction by three-dimensional echocardiography yields results comparable to those obtained by equilibrium radionuclide angiography and is substantially superior to all two-dimensional echocardiographic methods. Therefore, three-dimensional echocardiography may be used for accurate serial quantification of left ventricular function as an alternative to equilibrium radionuclide angiography.

Diagnosis of patent foramen ovale with transesophageal echocardiography in a patient supported with a left ventricular assist device.

Intracardiac right-to-left shunting through a patent foramen ovale is a known cause of arterial hypoxemia. We present a case report of a patient supported with a left ventricular assist device who had significant right-to-left shunting as visualized with transesophageal echocardiography. When the device was turned off, no further shunting occurred and arterial hypoxemia resolved. Our report is the first visual representation of the anatomy of a patent foramen ovale in a patient supported with a left ventricular assist device.

Management strategies for pulmonary vein thrombosis following single lung transplantation.

Pulmonary vein thrombosis following lung transplantation is an infrequently reported and often fatal vascular complication. Two cases of early pulmonary vein thrombosis following single lung transplantation are described. Both patients underwent surgical thrombectomy and anastomotic reconstruction following institution of cardiopulmonary bypass, but died of multiorgan failure within 5 days of diagnosis. The efficacy of transesophageal echocardiography as a diagnostic modality, as well as medical and surgical management strategies for thrombectomy, are discussed.

Intravascular ultrasound imaging of the Heartmate 1000 IP left ventricular assist device.

Left ventricular assist devices are increasingly used as a bridge to transplantation in patients with end-stage cardiac disease. Potential complications of these devices include thromboembolism and infection. Because conventional cardiac diagnostic techniques cannot be used to obtain an image of the interior of a left ventricular assist device, we assessed the ability of intravascular ultrasonography to obtain an image of the interior of the Heartmate 1000 IP left ventricular assist device. Feasibility of intravascular ultrasound imaging was initially demonstrated in vitro on a left ventricular assist device immersed in water. Five soft rubber masses were then placed in the device intake port adherent to the wall, and their images were obtained by intravascular ultrasonography. Excellent correlation between actual size and size as measured by intravascular ultrasonography was noted (long-axis, r = 0.98, short-axis, r = 0.89). After the device was implanted in two calves, intravascular ultrasound imaging was performed in vivo in the animals. The catheter was easily advanced through the device, and excellent images were obtained. In conclusion, intravascular ultrasonography can easily be used to obtain an image of the left ventricular assist device interior and can accurately assess the presence and size of abnormal masses inside the device. Intravascular ultrasonography may be clinically useful in evaluating cases of thrombus or vegetation related to left ventricular assist devices.

Incidence of pulmonary vein complications after lung transplantation: a prospective transesophageal echocardiographic study.

OBJECTIVES: This study attempted to document the incidence of pulmonary vein complications and their potential relation to clinical outcome in patients after lung transplantation. BACKGROUND: Several case reports have documented the presence of pulmonary venous thrombosis causing graft failure in patients after lung transplantation. Because the presentation of these complications mimics that of other postoperative problems, the true incidence of pulmonary vein abnormalities remains unclear. Transesophageal echocardiography is ideally suited to examine the pulmonary veins in the postoperative setting. METHODS: Twenty-one consecutive patients undergoing lung transplantation at our institution underwent transesophageal echocardiography within 32 days of transplantation (mean [+/- SD] 6.5 +/- 7.8 days). Special attention was placed on visualizing the pulmonary veins. RESULTS: Six (29%) of the 21 patients were noted to have abnormalities of the pulmonary veins in the vicinity of the anastomotic site. After follow-up of 30 days, 4 of these patients (67%) had significant cardiovascular morbidity, and 2 died, compared with 1 (7%) of 15 patients with normal pulmonary veins (p = 0.03). The degree of obstruction of the pulmonary vein appeared to correlate with short-term outcome. CONCLUSIONS: Abnormalities of the pulmonary veins are common after lung transplantation and are easily identified by transesophageal echocardiography. Occlusive thrombi appear to be detrimental to short-term outcome.

Coronary angiography in smokers undergoing evaluation for lung transplantation: is routine use justified?

Many patients referred for lung transplantation have a history of smoking. For the exclusion of the possibility of asymptomatic coronary artery disease, these patients undergo coronary angiography as part of their preoperative evaluation. The usefulness of this approach remains unknown. We reviewed the records of all smokers referred for lung transplantation who underwent coronary angiography (n = 77). Nine patients (12%) had significant coronary artery disease; six (8%) of these patients had their clinical management altered because of findings on angiography. Eight of nine patients with coronary artery disease (89%) and all of the six patients (100%) whose management was altered had coronary artery disease risk factors other than a history of smoking; therefore, no patient with clinically significant coronary artery disease had history of smoking as the only risk factor. The presence of other coronary artery disease risk factors was significantly associated (p < 0.0001) with the positive findings on angiography. A nonsignificant trend toward older age was found, and a higher proportion of male patients existed in the group with coronary artery disease. Routine angiography for all patients with a history of smoking referred for angiography is unjustified. A subset of patients with high risk identified primarily by the presence of additional coronary artery disease risk factors may benefit from routine angiography.