U. Scott Page

Aborted Off-Pump Coronary Artery Bypass Patients Have Much Worse Outcomes Than On-Pump or Successful Off-Pump Patients

Background—Off-pump coronary artery bypass graft (CABG) surgery is purported to reduce perioperative mortality and morbidity compared with on-pump coronary bypass graft surgery. However, the outcomes of patients for whom an off-pump strategy must be changed to an on-pump procedure during surgery have not been extensively studied. Methods and Results—The Merged Cardiac Registry (Health Data Research, Inc) contains 70 514 isolated CABG performed from January 1998 to March 2004 in 40 facilities. Among them, 62 634 patients begun and completed on-pump bypass (CPB); 7880 patients begun off-pump, of which 7424 (94.2%) completed off-pump coronary artery bypass (OPCAB), whereas 456 (5.8%) were converted to on-pump (CONVERT). CONVERT patients were more severely ill. The observed mortality of CONVERT, CPB, and OPCAB was 9.9%, 3.0%, and 1.6%, respectively, and the observed-to-predicted ratio was 2.77, 1.20, and 0.74, respectively. CONVERT also had more morbidity than either OPCAB or CPB. Finally, a risk model was created to identify patients who might be at risk for conversion from off-pump to on-pump CABG. Conclusions—Patients who are intended for an off-pump strategy and then require conversion to on-pump have significantly higher operative mortality and morbidity than either completed OPCAB or CPB patients. In addition, the operative mortality and morbidity are far in excess of that predicted preoperatively. Based on these results, strong consideration should be given for a planned strategy of CPB for those patients with preoperative hemodynamic instability requiring a salvage CABG operation, left ventricular hypertrophy, or previous CABG.

The Effect on Pulmonary Ultrastructure of Dacron-Wool Filtration During Cardiopulmonary Bypass

Abstract Lung biopsies from 37 patients undergoing open-heart surgery were studied to observe the effects of platelet-leukocyte aggregates on pulmonary fine structure following extracorporeal circulation. An examination of the pulmonary fine structure one hour after bypass revealed extensive occlusion of the capillary beds by aggregates of leukocytes in various stages of disintegration. In such areas the interalveolar septum exhibited perivascular edema. The endothelium of the affected vessels as well as the overlying type I alveolar epithelium appeared swollen and was frequently ruptured. The removal of leukocyte aggregates by Dacron-wool filtration was shown to reduce the extent of these degenerative lesions. Filters were placed in the coronary suction, primer, and arterial lines. The more complete the filtration was, beginning with the coronary suction line, the more normal the lungs appeared to be following bypass.

Long-Term Follow-up of Sequential Aortocoronary Venous Grafts

In 1972 we reported myocardial revascularization of 130 patients using multiple sequential aortocoronary anastomoses to a single saphenous vein ]1]. Of the 122 survivors described in that report, 121 (99%) have been followed an additional 3 years. Twelve deaths occurred during the interval. The 110 currently followed patients represent 290 anastomoses; 54 have been studied angiographically since operation. Angiographic patency at 3 years in the studied group (18) was 70%. These figures exceed our follow-up data for 135 patients revascularized during the same period using individual vein grafts. Comparison of life table survival curves demonstrates this result. We believe the improved patency and decreased operating time that have resulted from employing this technique have outweighed the likelihood of a proximal stenosis causing closure of the whole graft system. We continue to use this technique in combination with internal mammary artery grafts in the management of multiple-vessel coronary disease. Good early results using this technique have been reported by other authors [2, 3, 5].

Early experience with the intraluminal graft prosthesis

Surgical therapy for dissection of the thoracic aorta has been associated with a high mortality rate due in part to intraoperative bleeding at the suture lines and through the prosthesis. A technique has been devised to obviate some of these problems which utilizes a sutureless prosthesis that can be placed within the aorta. This device is now commercially available. Because of the infrequent use and the need to maintain a wide variety of lengths and diameters of these grafts, several Portland area hospitals jointly purchased grafts to reduce inventory and cost. From November 1981 through September 1982, four patients in two Portland area hospitals were treated with intraluminal grafts for descending thoracic dissections. All patients survived the surgical treatment and were discharged without complications. Based on a review of the literature and our initial experience, the intraluminal prosthesis appears to represent a significant improvement over conventional graft placement for treatment of both acute and chronic aortic dissection.

Emboli (debris) produced by bubble oxygenators. Removal by filtration.

Abstract The screen filtration pressure (SFP) and its derivative, the screen filtration resistance (SFR), were measured in blood in the extracorporeal circuit of humans during cardiopulmonary bypass. It was confirmed that blood from the suction line had very high SFP and SFR. These were returned to normal by filtration through Dacron wool. During the first few minutes of bypass the SFR of venous blood was high, but thereafter it remained low. The SFR of oxygenated blood was elevated continuously during the procedure, especially after nearly 2 hours of bypass. Arterial blood consistently had a low SFR after Dacron-wool filtration. The high SFR values following oxygenation are interpreted as being due to particle (microemboli) production by the oxygenator. These were uniformly removed by a Dacron-wool arterial filter.

Transthoracic intraaortic balloon cannulation to avoid repeat sternotomy for removal.

Cannulation of the ascending aorta for intraaortic balloon assistance is a practical alternative to the standard transfemoral cannulation in patients with significant aortoiliac occlusive disease. One disadvantage of ascending aortic cannulation has been the requirement for a repeat sternotomy to remove the balloon. This report describes the successful implementation in 2 patients of a technique of ascending aortic balloon insertion and removal that avoids a second sternotomy.

Aprotinin use in patients with dialysis-dependent renal failure undergoing cardiac operations ☆ ☆☆ ★ ★★ ♢ ♢♢

closure technique. Histologically, it was proved in these patients that the cancer affected only the external layer of the aortic wall. CT was a feasible means of judging whether malignant tumor had invaded the aorta by observing the motion of the tumors along the aortic wall. This method could be used for either purpose-to discriminate T4 tumors from others as a contraindication for resection or to devise a strategy for concomitant resection of the aorta. Provided an invaded portion of the aorta, which is in contact with the immobile surface of a tumor, has been revealed clearly before the operation, a circulatory bypass and prosthesis required for resection and replacement of the wall can be arranged appropriately. In our seven cases, we took advantage of the new imaging modality in this way. In our series, one tumor in contact with the distal arch was erroneously judged to be invasive. The most likely reason for this misdiagnosis was that the tumor was located on the distal arch near the pulmonary hilus and thus showed barely detectable upward and downward motion during breathing. For the same reason, a noninvasive tumor located on the diaphragm near the pulmonary ligament might be judged invasive by mistake. To avoid such misdiagnoses of pulmonary tumors located on the distal arch or diaphragm, the investigator should use the heartbeat mode as well as the breathing mode for more accurate evaluation, rather than using the breathing mode alone. It is still difficult to discriminate between invasion and fibrous adhesion. We believe that cine CT should reveal malignant adhesion distinctly, because such invasion shows tougher attachment with less mobility than simple fibrous adhesion. A study including more patients will be required to address this issue.

Revascularization of the heart: Aortocoronary bypass in sixty-three patients☆

Abstract Aorta-to-coronary artery bypass procedures utilizing reversed saphenous vein grafts were performed in sixty-three patients, 117 grafts being placed. Symptomatic patients studied had 38.8 per cent patency of the grafts and asymptomatic patients had a 95 per cent patency rate. Hospital mortality was 7.8 per cent. Forty-five patients (71 per cent) are asymptomatic.

Response to Letters Regarding Article “Aprotinin Does Not Increase the Risk of Renal Failure in Cardiac Surgery Patients”

We would like to thank Drs Karkouti, Beattie, Bouchard, Mathew, Metha, Agoustides, Landis, Taylor, and Poston for their interest in our study1 and their comments. We agree wholeheartedly with Drs Landis, Taylor, and Poston. We also agree with Dr Agoustides that the inclusion of angiotensin-converting enzyme inhibitor therapy and detailed dose information for aprotinin would lend further discrimination to our model. Unfortunately, although we wished to include such potential confounders in our analysis, these variables were not available in our dataset. We applaud Drs Bouchard, Mathew, and Metha for pointing out the universal flaw of this sort of research: that is, the lack of a uniform definition of clinically significant renal dysfunction. Retrospective analyses do not allow for the inclusion of >6 hours of oliguria, although prospective trials might. Because Mangano et al2 and Karkouti et al3 used differing definitions of renal dysfunction based on either …

Early experience with mitral valve reconstruction for mitral insufficiency

Mitral valve repair for mitral regurgitation has been reported to have more favorable early and late results than mitral valve replacement. From July 1985 through July 1990, 63 patients have undergone valve repair at Good Samaritan Hospital. Twenty-two men and 41 women whose ages ranged from 34 to 81 years (mean 67.9 years) were treated. Twenty-eight patients were in New York Heart Association functional class III or IV. Twelve (19%) had undergone prior cardiac surgery. Isolated valve repair was performed in 18 patients. Valve repair was combined with coronary artery bypass grafting, other valve procedures, or aneurysm resection in the remainder (71%). Two patients (3%) died while in the hospital, and four deaths (one valve-related) occurred after discharge. Leaflet resection for ruptured chordae was done in 24 patients (38%), chordal shortening in 5 patients (8%), and leaflet transposition in 2 patients. Rigid ring annuloplasty (Carpentier) was performed in 62 patients. Eight patients required mitral valve replacement at the same operation because of unsatisfactory valve repair. Results of valve repair evaluated by echocardiography at discharge show that 48 patients (88%) are free of significant regurgitation. Follow-up to date reveals that all surviving patients who underwent valve repair have clinically improved and are stable. Four of five patients with moderate mitral regurgitation are currently asymptomatic. There have been two valve-related late failures requiring reoperation. Based on this early experience, we conclude that valve repair compared with mitral valve replacement has a low operative mortality with good early results. Continued efforts to preserve native mitral valve function in the presence of mitral regurgitation appear justified.