Coronary artery reoperations. Early and late results in 101 patients

Aortic valve replacement after coronary artery bypass grafting with the in situ right gastroepiploic artery to the occluded right coronary artery using a temporary vein graft for cardioplegia

Background

The operation of aortic valve replacement (AVR) after CABG is a technically challenging procedure in respect to dissection of living grafts from its surrounding tissue, myocardial protection, and so on, especially that procedure to patients with living in situ functional arterial grafts to occluded native coronary arteries has a special problem in regard to myocardial protection because myocardial blood supply originates from various arteries including the left internal thoracic artery (LITA), the right internal thoracic artery (RITA), and the right gastroepiploic artery (GEA); hence, adequate myocardial protection should be fastidiously considered.

Case presentation

A 68-year-old woman, who underwent CABG comprised of the in situ LITA to the LAD, the in situ GEA to the RCA, and the saphenous vein graft (SVG) to the obtuse marginal branch of the left circumflex artery (LCX) to the triple vessel coronary disease 9 years before, was referred to our hospital due to the aortic valve stenosis.

Conclusion

We successfully underwent an aortic valve operation to a patient with a functioning LITA to the occluded left anterior descending artery and a GEA to the right coronary artery (RCA) by using a temporary vein graft to the RCA for the infusion of cardioplegic solution in addition to the conventional antegrade and retrograde cardioplegic infusions with ice slush topical cooling.

Impact of Preoperative 64-Slice CT Scanning on Mini-Maze Atrial Fibrillation Surgery

BACKGROUND

: Multidetector computed tomography (MDCT) is emerging as a powerful noninvasive diagnostic tool. The appropriate role of this technique in the preoperative evaluation of cardiovascular disease has yet to be fully defined. Atrial fibrillation is the most common sustained cardiac arrhythmia, and novel minimally invasive surgical techniques have been developed to treat this condition by electrically isolating the pulmonary veins. The ideal methodology to preoperatively evaluate these patients remains debatable. We hypothesized that 64-slice CT could significantly affect perioperative planning.

METHODS

: Thirty-six consecutive patients who consented to undergo minimally invasive pulmonary vein isolation at our institution underwent a preoperative 64-slice cardiac CT scan. All cardiac and noncardiac abnormalities were recorded, and modifications to the initial surgical plan were documented.

RESULTS

: The mean patient age was 64.4 ± 11.9 years [26 men (72.2%), 17 with known coronary artery disease (47.2%)]. Preoperative CT scanning detected 12 patients with abnormal pulmonary venous anatomy (33.3%), 3 with left atrial thrombus (8.3%), and 17 with significant coronary artery disease (47.2%). Furthermore, 20 studies (55.6%) detected pulmonary abnormalities (including 11 nodules). Preoperative scanning significantly altered surgical planning in 10 cases (27.8%). Alterations in patient treatment included preoperative invasive angiography, conversion of the mini-maze to an open chest procedure, alteration of surgical approach, and postponement/cancellation.

CONCLUSIONS

: Sixty-four-slice CT scanning is a safe, rapid, and accurate procedure with important ramifications for surgical planning. This methodology could become an alternative approach to screen preoperative cardiac surgical patients.

Do you need to clamp a patent left internal thoracic artery-left anterior descending graft in reoperative cardiac surgery?

BACKGROUND

Dogma suggests optimal myocardial protection in cardiac surgery after prior coronary artery bypass graft surgery (CABG) with patent left internal thoracic artery (LITA) pedicle graft requires clamping the graft. However, we hypothesized that leaving a patent LITA-left anterior descending (LAD) graft unclamped would not affect mortality from reoperative cardiac surgery.

METHODS

Data were collected on reoperative cardiac surgery patients with prior LITA-LAD grafts from July 1995 through June 2006 at our institution. With the LITA unclamped, myocardial protection was obtained initially with antegrade cardioplegia followed by regular, retrograde cardioplegia boluses and systemic hypothermia. The Society of Thoracic Surgeons National Database definitions were employed. The primary outcome was perioperative mortality. Variables were evaluated for association with mortality by bivariate and multivariate analyses.

RESULTS

In all, 206 reoperations were identified involving patients with a patent LITA-LAD graft. Of these, 118 (57%) did not have their LITA pedicle clamped compared with 88 (43%) who did. There were 15 nonsurvivors (7%): 8 of 188 (6.8%) in the unclamped group and 7 of 88 (8.0%) in the clamped group (p = 0.750). Nonsurvivors had more renal failure (p = 0.007), congestive heart failure (p = 0.017), and longer perfusion times (p = 0.010). When controlling for independently associated variables for mortality, namely, perfusion time (odds ratio 1.014 per minute; 95% confidence interval: 1.004 to 1.023; p = 0.004) and renal failure (odds ratio 4.146; 95% confidence interval: 1.280 to 13.427; p = 0.018), an unclamped LITA did not result in any increased mortality (odds ratio 1.370; 95% confidence interval: 0.448 to 4.191). Importantly, the process of dissecting out the LITA resulted in 7 graft injuries, 2 of which significantly altered the operation.

CONCLUSIONS

In cardiac surgery after CABG, leaving the LITA graft unclamped did not change mortality but may reduce the risk of patent graft injury, which may alter an operation.

Apicoaortic valved conduit: Potential for progress?

OBJECTIVE

The number of elderly patients who require aortic valve replacement is growing, as is the increase of complicating factors, such as previous coronary bypass grafting and atherosclerotic disease of the ascending aorta. An uncommon surgical option to aortic valve replacement is the apicoaortic valved conduit. In this article the techniques and outcomes of 13 cases of apicoaortic valved conduit insertions in high-risk patients are described.

METHODS

From 2002 through 2005, 13 patients (mean age, 75 +/- 8.7 years; 8 men) with severe calcific aortic stenosis had insertions of an apicoaortic valved conduit because of a porcelain aorta (n = 4), previous coronary bypass grafting (n = 6), or both (n = 3). The off-pump technique was used in 9 patients, and a heparinized miniextracorporeal circulation system was used in 4 patients. Follow-up time was 6 to 33 months.

RESULTS

Mean intensive care stay was 2 +/- 2.7 days, and mean hospital stay was 12 +/- 8 days. The 30-day mortality was 15% (2 patients; postoperative days 3 and 28, both caused by myocardial infarction). Mortality later than 30 days postoperatively was 23% (3 patients; postoperative day 45 caused by bilateral pulmonary bleeding because of pneumonia, postoperative day 56 caused by myocardial infarction, and postoperative day 81 caused by pneumonia). The remaining 8 patients were doing well, all in New York Heart Association class I or II at follow-up, with echocardiography showing a low gradient over the valved conduit.

CONCLUSIONS

The apicoaortic valved conduit in high-risk patients undergoing aortic valve replacement remains a feasible option, with a substantial potential for technical development and progress.

Supraclavicular control of patent internal thoracic artery graft flow during aortic valve replacement

BACKGROUND

The mortality and morbidity of aortic valve replacement (AVR) after prior coronary artery bypass surgery (CABG) with patent left internal thoracic artery (LITA) is significant. The risk of LITA injury and inadequate myocardial preservation during the cross-clamp period may cause myocardial pump failure.

METHODS

A total of 43 patients with a patent LITA graft underwent AVR. The patients were divided into the two groups. Group 1 included 19 patients who underwent AVR with deep hypothermia (20 degrees C) without LITA clamping. Group 2 included 24 patients in whom LITA flow was controlled through supraclavicular occlusion and AVR performed with moderate hypothermia (28 degrees C).

RESULTS

Average cardiopulmonary bypass time (CPB) time was 118.79 +/- 20.36 minutes in group 1 and 102.67 +/- 9.66 minutes in group 2 (p = 0.006). Average cross-clamp time was 53.79 +/- 7.26 minutes in group 1 and 49.63 +/- 6.7 minutes in group 2 (p = 0.022). Inotropic support was required in 12 patients in group 1 and 4 patients in group 2 (p = 0.002). Average intensive care unit stay was 4.68 +/- 2.24 days in group 1 and 2.29 +/- 0.46 days in group 2 (p < 0.001). Average hospital stay was 11.84 +/- 2.91 days in group 1 and 8.04 +/- 2.38 days in group 2 (p < 0.001). Mortality due to myocardial failure developed in 4 patients in group 1 but in none of the patients in group 2 (p = 0.02).

CONCLUSIONS

Proximal control of LITA flow by extrathoracic supraclavicular occlusion reduces the incidence of myocardial failure due to nonhomogenous cardioplegia delivery to the anterior wall of the heart, resulting in improved myocardial protection and the elimination of the need for deep hypothermia.

Aortic valve surgery after previous coronary artery bypass grafting with functioning internal mammary artery grafts

BACKGROUND

Aortic valve surgery after coronary artery bypass grafting (CABG) in the setting of patent pedicled internal mammary artery (IMA) grafts poses a high risk because of the underlying ischemic and valve disease. Unlike mitral valve surgery or CABG, in which aortic clamping (AoX) may be optional, aortic valve surgery uniformly requires AoX unless circulatory arrest is used. Management of the IMA graft in these circumstances has traditionally involved dissection and clamping to prevent regional myocardial warming and cardioplegia "washout" during AoX. An alternative strategy involves avoiding dissection of the IMA, leaving the IMA graft open and establishing moderate-to-deep hypothermia during AoX and cardioplegic arrest. To date, no study has been published documenting the safety and efficacy of the latter practice.

METHODS

A total of 94 patients who had patent IMA graft and underwent aortic valve surgery under AoX and cardioplegia between April 1992 and March 2001 were analyzed. The IMA was avoided and left open during AoX, and the patients were cooled systemically (median 20 degrees C). Patients ranged in age from 55 to 90 years (median 73.5 years). Ejection fraction was 15% to 83% (median 50%). Of the patients, 18 (19%) underwent minimally invasive upper hemi-resternotomy. Analysis for predictors of outcome was performed.

RESULTS

The operative mortality, perioperative myocardial infarction (MI), and stroke rates were 6.4%, 7%, and 11%, respectively. No significant independent predictors of operative mortality or MI could be identified in the multivariate analysis, although a trend was shown for operative mortality with urgent procedures and patients requiring concomitant surgery of the ascending or arch aorta or aortic root. Advanced age and prolonged cardiopulmonary bypass predicted stroke in the multivariate analysis. There were five (5%) IMA injuries, all occurring during reentry or mediastinal dissection, but none in the subgroup of patients who underwent minimally invasive procedures. All patients survived.

CONCLUSIONS

Patients undergoing aortic valve surgery after CABG in the presence of patent IMA represent a potentially high-risk group. Because AoX is almost uniformly required, a decision regarding the management of the IMA pedicle is needed. We have found that leaving the IMA undissected and unclamped is a reasonable strategy, provided that systemic cooling for myocardial protection is established to prevent regional warming and to compensate for cardioplegia washout effect during AoX.

Approach to the mitral valve through a right thoracotomy in potentially hazardous reoperation

BACKGROUND

Repeat sternotomy for mitral valve surgery may be hazardous in some patients. A right thoracotomy avoids the densely scarred area beneath the sternum and provides adequate in-line exposure of the mitral valve.

METHODS

Between 1994 and 1997, five patients were reoperated for a mitral valve or prosthesis dysfunction through a right thoracotomy. Indications were three second redo-mitral valve surgeries and two first redo, once in a patient with an aortic prosthesis and once in a patient with patent aortocoronary grafts. The operation was performed without clamping the ascending aorta in moderate hypothermic (four patients) or normothermia (one patient).

RESULTS

Exposure of the mitral valve for replacement (four patients) or for repair of a paraprosthetic leak (one patient) was optimal in all patients. Resumption of cardiac function occurred rapidly after repair without specific support. Postoperative course was uncomplicated. Blood loss ranged from 300 to 700 mL. Patients were discharged from 7 to 12 days postoperatively. They are in New York Heart Association (NYHA) functional Class I (four patients) and II (one patient), from 3 to 42 months postoperatively.

CONCLUSION

Right thoracotomy provides a direct "in the line of vision" access to the mitral valve. Because complete de-airing of the heart is difficult and respiratory function depressed after a right thoracotomy, this approach seems suitable when technical difficulties are expected in sternal reopening.

Injury to a patent left internal thoracic artery graft at coronary reoperation

BACKGROUND

The purpose of this study was to determine the prevalence, outcome, and operative strategies for patients having injury to a patent left internal thoracic artery (LITA) graft to the left anterior descending coronary artery (LAD) at coronary reoperation.

METHODS

Of 655 patients with a patent LITA graft to the LAD undergoing coronary reoperation from 1986 to 1997, 35 (5.3%) sustained intraoperative injury to the LITA graft.

RESULTS

Strategies to restore flow to the LAD included new saphenous vein graft to the LAD in 15 patients, saphenous vein graft to the LITA stump in 7, saphenous vein graft to the LAD and repair of the LITA graft in 6, and other strategies in 7. All or part of the LITA graft to the LAD was salvaged in 20 patients (57%). Fourteen patients (40%) sustained perioperative myocardial infarction, and 3 patients died (8.6%). The 3 patients who died all had stenosis or thrombosis of the graft to the LAD documented at autopsy.

CONCLUSIONS

We conclude that (1) the prevalence of injury to a patent LITA graft is 5.3%; (2) a variety of techniques can be used to restore blood flow to the LAD; and (3) ineffective revascularization of the LAD in this situation is associated with operative mortality. At primary coronary artery bypass grafting, the LITA pedicle should be positioned in the left chest away from the posterior sternal table; this strategy may minimize the risk of LITA graft injury at coronary reoperation.

Myocardial perfusion after coronary artery bypass surgery. A study using ectomographic myocardial scintigraphy and adenosine provocation

A study was conducted to determine the time dependency of myocardial perfusion improvement after coronary artery bypass graft (CABG) surgery. Seventeen 3-vessel diseased patients (16 male, 1 female) scheduled for CABG surgery from a cardiac surgical and intensive-care unit were examined. Ten of the 17 patients returned for examination after 1 year. A titrated adenosine infusion was used to expose reversible ischemia. Tc99m-sestamibi was injected at rest and at maximum adenosine infusion rate, and isotope distribution was determined using ectomographic myocardial scintigraphy. Visually scored percent isotope uptake defect size and percent uptake reduction were assessed. It was found that resting isotope uptake defects were unchanged 1 h after surgery, increased in severity after 1 week, and after 1 year were 24% less than the preoperative scores (p < 0.01) and 55% less than after 1 week (p < 0.001). It was found that adenosine infusion induced a 57% increase in average defect score preoperatively (p < 0.001) but no increase postoperatively. No differences were seen between regions supplied by arterial or venous grafts. Isotope uptake defects increased between 1 h and 1 week after CABG surgery, and after 1 year the scores were less than those recorded preoperatively and after 1 week. Adenosine-induced reversible isotope uptake changes seen preoperatively were eliminated postoperatively in all vessel regions.

Acute occlusion of a left internal mammary artery graft immediately after redo coronary artery bypass surgery: successful rescue PTCA

A patient with a patent left internal mammary artery (LIMA) to the left anterior descending (LAD) artery required repeat bypass grafting to the distal right coronary artery (RCA). Intraoperative injury to the LIMA resulted in acute anterior myocardial infarction, which was managed by successful rescue percutaneous transluminal coronary angioplasty (PTCA).

Reoperative coronary grafting: changing patient profiles, operative indications, techniques, and results

To assess the changing trends in patient profiles, operative indications and techniques, and their impact on the results of reoperative myocardial revascularization, we reviewed the records of 750 consecutive patients who had an isolated first reoperation for coronary artery disease at the Massachusetts General Hospital from 1977 to 1992. The patients were chronologically grouped into three equal cohorts of 250 patients. Our assessment over time revealed a significantly (p < 0.03) increased incidence of the following: older age, peripheral vascular disease, grafts at the first revascularization, longer operative interval, interval infarctions and angioplasties, and congestive heart failure and unstable angina requiring greater use of preoperative intraaortic balloon pumping. At catheterization significantly more left main coronary disease, lower ejection fractions, and more patent but diseased grafts were found. The reoperations were significantly done more urgently, with more grafts placed and a greater use of mammary artery grafting. Despite these increased risks over time, median postoperative hospital stay was significantly shortened (p < 0.001), though hospital mortality (5.3%) and perioperative myocardial infarction (6.3%) did not change significantly. Significant multivariate predictors of hospital death were nonelective operation, perioperative myocardial infarction, prior myocardial infarction, and mammary artery grafting at the initial operation.

Repeat coronary artery bypass grafting

In 1981-1989 we performed repeat coronary artery bypass grafting on 42 men and 10 women (mean age 55 years) with angina pectoris recurring on average 27 months after the primary operation. The cause was occlusion or stenosis of vein grafts alone (59%) or in combination with progression of native coronary atherosclerosis (31%) or progression in the native circulation without graft failure (10%). Complications at the repeat operation included five lesions of the right ventricle and five lesions of patient grafts. The 30-day mortality was 3.8% (95% confidence limits 0.5-13.2%). Survival after observation averaging 2 1/2 years was 92.3% (95% confidence limits 81.5-97.9%). Angina pectoris was completely relieved after the operation in 48% of the patients, lessened in 35% and unchanged in 17%. Although repeat coronary artery bypass grafting carries heightened mortality and morbidity, and the results are less satisfactory than after first-time bypass, the operation can be worthwhile.

Indications for and risks in reoperation for coronary artery disease

Seventy-one coronary artery bypass grafting (CABG) reoperations were performed during a 17-year period, comprising 2.7% of all CABG operations. The main indication (in 87%) was vein graft failure alone or combined with other causes. Progression of disease in native coronary arteries was the sole indication in only 4 of the 71 cases. There were seven perioperative deaths, mainly due to myocardial infarction. Significant perioperative complications arose in 36 cases, including intraoperative lesion of a previous left internal mammary graft (16.2%) or of the right ventricle or anterior descending branch of the left coronary artery (2.8%). Postoperative low output syndrome appeared in 13 patients (18.3%), in seven of whom myocardial infarction was verified. Postoperative bleeding required resternotomy in six cases (9.1%). Because of the heightened operative mortality and morbidity risks, indications for redo CABG should be individualized. A well functioning internal mammary artery graft may be a relative contraindication. Accurate knowledge of the previous operation is essential and, especially in young patients, the possibility of reoperation should be taken into consideration at initial CABG.