William F. Pharr

Efficacy and Cost-Effectiveness of Preoperative IABP in Patients with Ejection Fraction of 0.25 or Less

BACKGROUND The purposes of this study are to determine whether patients with severe left ventricular dysfunction benefit from prophylactic insertion of an intraaortic balloon pump and to evaluate its cost-effectiveness. METHODS Between January 1991 and December 1995, 163 consecutive patients with a left ventricular ejection fraction of 0.25 or less underwent isolated coronary artery bypass grafting. An intraaortic balloon pump was inserted before operation in 37 patients (group A). The remaining 126 patients underwent operation without preoperative insertion of the device (group B). Preoperatively, 91.9% (34/37) of group A patients and 54.8% (69/126) of group B patients were in New York Heart Association functional class III or IV (p < 0.001). RESULTS The 30-day mortality rate was 2.7% (1/37) and 11.9% (15/126) for groups A and B, respectively (p < 0.005). All deaths occurred in patients in functional class III or IV. In group B, 28 patients (22.2%) required an intraaortic balloon pump after cardiotomy for low cardiac output, 42.9% (12/28) of whom died. Median postoperative hospital stay was 9.9 days and 12.0 days, and mean hospital charges were

Which Is the Graft of Choice for the Right Coronary and Posterior Descending Arteries? Comparison of the Right Internal Mammary Artery and the Right Gastroepiploic Artery

50,627 and

Comparison of reactive hyperemia and treadmill tests in the evaluation of peripheral vascular disease

54,818 for survivors in groups A and B; respectively (p = not significant). CONCLUSIONS Our experience suggests that patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting may benefit from preoperative intraaortic balloon pump insertion, especially patients in functional class III or IV. This approach improved survival significantly, reduced hospital stay, and was more cost-effective.

A quantitative method for the evaluation of spectral analysis patterns in carotid artery stenosis

BACKGROUND The graft of choice for the left anterior descending coronary artery is the left internal mammary artery because of superior long-term patency. However, controversy exists regarding the graft of choice for the right coronary artery and for the posterior descending branch. METHODS AND RESULTS Two types of pedicled arterial grafts were used for the right coronary and the posterior descending arteries in patients undergoing coronary bypass surgery between January 1991 and September 1994. Group A comprised 114 patients with a right internal mammary artery (RIMA) graft, and group B consisted of 127 patients with an in situ right gastroepiploic artery (R-GEA) graft. Mean age was 56.9 years in group A and 63.3 years in group B; 7.9% (9 of 114) and 33.9% (43 of 127) were diabetics in groups A and B, respectively. Overall mortality was 2.6% (3 deaths) for group A and 3.9% (5 deaths) for group B (P = NS). However, the prevalence of perioperative myocardial infarction in the right coronary artery distribution was significantly higher for group A (5.3%, or 6 of 114) than for group B (0.8%, or 1 of 127; P < .05), and the reoperation rate for graft failure (from 0 to 12 months after surgery) was significantly higher for the RIMA (4.4%, or 5 of 114) than for the R-GEA (0%; P < .05). Also, the prevalence of deep sternal wound infection in diabetics was significantly higher in group A (22.2%, or 2 of 9) than in group B (4.6%, or 2 of 43; P < .05). CONCLUSIONS Our preliminary results suggest that the failure rate of the RIMA graft is significantly higher, especially if used as a pedicled graft to the posterior descending artery. The risk of sternal wound complications is greater in diabetics if both internal mammary arteries are used for grafting. Therefore, the R-GEA graft is preferred in diabetics and whenever the posterior descending artery is the target vessel.

Objective Criteria for the Interpretation of Carotid Artery Spectral Analysis Patterns

The systolic ankle pressure response to thigh cuff occlusion (reactive hyperemia test) was compared with a similar measurement after treadmill exercise in 48 limbs of 24 normal volunteers. The reactive hyperemia test was then performed on 26 legs in 16 patients with clinical evidence of arterial disease of the leg and abnormal treadmill tests (mean decrease 39 +/- 24 percent). No decrease in pressure occurred in normal subjects after exercise. All control subjects demonstrated a decrease in pressure after thigh cuff occlusion (34 +/- 7.9 percent). The percent pressure decrease during reactive hyperemia in the abnormal group was significantly lower (49.7 +/- 19 percent; p less than 0.001). There was a high correlation between the percent decrease in pressure during reactive hyperemia and the decrease after exercise in the claudicants (r = 0.69; p less than 0.001). However, the percent pressure decrease in 13 of the 26 abnormal patients fell within 2 standard deviations of the reactive hyperemia control group mean. The range of the pressure decreases in these 13 patients, 16 to 48 percent, was shared by 47 of the 48 normal subjects. The findings in this study are inconsistent with those in previously published reports and suggest that reactive hyperemia testing cannot be used interchangeably with the treadmill exercise test.

Implantation of the Distal Aorta: A Technique for Preservation of Pelvic Blood Flow in Aortofemoral Reconstruction

Duplex scanning in conjunction with Fast Fourier Transform Spectral Analysis offers a means of identifying stenotic internal carotid arteries, but few quantitative algorithms for interpretation of the spectral analysis patterns have been described. We first developed two objective parameters for analyzing carotid artery spectral analysis patterns which included a total of three peak frequencies in diastole and a ratio of spectral pattern areas between the internal and common carotid vessels. We then devised a formula for interpretation of the test results based on a computerized, best-fit, step-wise, discriminate analysis performed on 196 angiographically studied carotid vessels. This formula was then prospectively applied to 154 other carotid arteries with independently interpreted angiograms. 103/109 (94%) of the carotid arteries with less than 50% angiographic stenosis were correctly identified as were 40/50 (89%) of the vessels with 50% or more narrowing. Combining these groups with 16/17 (94%) properly classified total occlusions resulted in an overall accuracy rate of 93%. Application of the formula to smaller subgroups also showed significant differences in the formula means as they related to the degree of angiographic stenosis. Duplex scanning in conjunction with spectral analysis offers a reliable screening test for the evaluation of patients with suspected carotid artery stenosis.

Intrapleural haemorrhage complicating pulmonary arteriovenous fistula

The duplex scanner (imager + pulsed Doppler) in combination with a fast Fourier transform spectrum analyzer has been used to identify areas of arterial narrowing. To evaluate its effectiveness in the detection of clinically significant carotid stenosis, 1 previously described and 2 original objective parameters were applied to the real time sound frequency tracings from 157 carotid arteries that also had angiograms available to determine the presence and degree of stenotic involvement. There was a statistically significant difference between the means of the test scores of the group of vessels with high grade narrowing (greater than or equal to 60%) and those with less than 40% stenosis for all 3 criteria. Of major clinical interest were our 2 parameters, the 3-point diastolic internal carotid frequency total and the internal-to-common carotid spectral area ratio, both of which showed considerable promise as predictors of stenotic disease. For each test, 40/46 (87%) of the test scores of the arteries with 50% or greater narrowing fell outside 2 standard deviations (95% confidence level) of the means of the vessels with less than 50% stenosis. A previously reported parameter, the internal-to-common carotid peak systolic frequency ratio, was notably less discriminant in this regard.

Abbreviated Aortic Insufficiency in Aortic Dissection Caused by Prolapse of the Intimal Flap

We report our initial experience with a previously undescribed variation of aortofemoral bypass. This technique is an alternative to end-to-side aortic anastomosis for preservation of pelvic blood flow. It involves an end-to-end proximal aortic anastomosis with implantation of the distal aorta into the posterior wall of the bifurcation graft. This approach has been used selectively for nine patients. Seven patients operated on using this technique had bilateral external iliac artery disease preventing retrograde perfusion of the pelvis. We used this procedure in two other young patients to preserve large inferior mesenteric and distal aortic lumbar vessels proximal to common iliac artery occlusions. Mean follow-up has been 20 months. There have been no deaths and no major complications. This technique provides the hemodynamic benefit of a proximal end-to-end aortic anastomosis while maintaining patency of the distal aorta and its branches. Additional technical advantages may include better suture line protection from the duodenum and a decreased potential for graft limb kinking. These factors may ultimately result in superior long- term graft patency.

Evaluation of the peak frequency ratio (PFR) measurement in the detection of internal carotid artery stenosis

Rupture of a pulmonary arteriovenous fistula caused intrapleural haemorrhage in a young woman with hereditary haemorrhagic telangiectasia and multiple bilateral fistulas. Bleeding was limited and exsanguination was probably prevented by pleural adhesions. Treatment included decortication, excision of the bleeding fistula, and prophylactic sclerosis of the opposite pleural space.

Unusual presentations of abdominal aortic aneurysms.

Aortic insufficiency was identified in a patient with acute ascending aortic dissection. The aortic insufficiency was limited to the first half of diastole by prolapse of the intimal flap against the regurgitant orifice. This unusual pathophysiology was well demonstrated by two-dimensional and color flow Doppler echocardiography.