Seventeen-year experience with bilateral internal mammary artery grafts

The use of the gastroepiploic artery for peripheral revascularisation. A study in pigs

OBJECTIVES

To use the autologous gastroepiploic artery (GEA) as arterial bypass graft for peripheral revascularisation. We compared the development of intimal hyperplasia and nitric oxide (NO) capacity in GEA and internal jugular vein (IJV) implanted as peripheral grafts.

MATERIALS AND METHODS

In pigs the GEA was implanted into the right peripheral circulation as a femoropopliteal bypass graft. In the left peripheral circulation the IJV was implanted as a femoropopliteal graft. After 21 days all grafts were harvested. Vascular rings of each graft before and after operation were studied for NO capacity. The distal half of each graft was prepared for histomorphometric studies.

RESULTS

Administration of bradykinin to IJV and GEA induced relaxation. After implantation bradykinin resulted in contraction in IJV grafts, whereas in GEA grafts relaxation was reduced. In IJV grafts extensive intimal hyperplasia was formed, whereas in GEA grafts only small areas of intimal hyperplasia were formed.

CONCLUSIONS

The functional studies lost NO capacity in IJV grafts, whereas NO capacity in GEA grafts remained intact. Intimal hyperplasia in IJV grafts was extensive, whereas GEA grafts demonstrated preservation of pre-existent intimal architecture. These results may encourage the application of the human GEA as bypass graft for reconstruction of arteries in the lower limb or foot.

Minimally invasive coronary artery bypass grafting using the right gastroepiploic artery

BACKGROUND

Anastomosis of the left internal thoracic artery to the left anterior descending artery without sternotomy and without cardiopulmonary bypass is a standard approach in minimally invasive coronary artery bypass grafting. To expand the indications for minimally invasive coronary artery bypass grafting from one-vessel disease to two-vessel disease, we began to perform anastomosis of the right gastroepiploic artery (RGEA) to the right coronary artery (RCA).

METHODS

From February to November 1996, an RGEA graft was used in 25 of the 100 patients who underwent minimally invasive coronary artery bypass grafting at our clinic. Eleven of the patients had only RCA disease and 14 had both RCA and left anterior descending artery disease. One of the operations was a redo coronary artery bypass grafting. The RGEA was anastomosed to the RCA through a laparotomy incision and the left internal thoracic artery was anastomosed to the left anterior descending artery through a left anterior thoracotomy. In 5 patients, the RGEA was lengthened by venous grafting.

RESULTS

All patients underwent angiography after operation; 82.6% of the RGEA grafts and all the left internal thoracic artery grafts were functioning well. In three of the four nonvisualized RGEA grafts, the percentage of proximal stenosis of the RCA seen on postoperative angiography was not critical (40%, 50%, and 50%, respectively), allowing significant competitive flow through the native bypassed RCA. The patency of all the RGEA grafts without competitive flow was 95%, with a 95% confidence interval of 75.1% to 99.9%.

CONCLUSIONS

The indications for minimally invasive coronary artery bypass grafting could be extended to primary operations in patients with left anterior descending artery and RCA lesions by using both the left internal thoracic artery and the RGEA.

[The propriety of bilateral internal thoracic artery grafting in women]

In our institution, the exclusion criteria of the bilateral internal thoracic artery (BITA) grafting include age over 70 years old, obesity, severe diabetes, renal dysfunction and poor preoperative physical activity. The objective of this study is to evaluate propriety of the use of bilateral internal thoracic artery for coronary artery bypass grafting (CABG) in women. Clinical outcome of female patients who underwent BITA grafting (group B-F; n = 50) was compared with that of female patients who underwent single internal thoracic artery grafting (group S; n = 50). In addition, clinical outcome of the male patients who underwent BITA grafting (group B-M; n = 50) was compared with that of group B-F. Between group B-F and S, the age, prevalence of obesity and that of renal dysfunction were significantly different, which was predictable because of the group selection according to the criteria. However, the prevalence of previous myocardial infarction and that of left ventricular dysfunction and the extent of coronary artery disease were not significantly different. Whereas, between group B-F and B-M, preoperative factors were not significantly different except the body size. Intraoperative technical factors, such no of grafts, aortic cross clamp time, cardiopulmonary bypass time, rate of complete revascularization, were not significantly different. In comparison of group B-F with group B-M, the site of anastomosis with arterial grafts were not significantly different. Patency rate of arterial and venous grafts two week after operation was not significantly different. Either postoperative complications, such as reoperation for bleeding, wound complication, low output syndrome, renal dysfunction etc, were not significantly different. One patient (2%) in group B-F and 1 patient (2%) in group B-M died in the hospital (p > 0.05). In summary, BITA can be a viable conduit of choice for CABG in female patients as well as that in male patients. Criteria of the use of BITA is recommended to exclude preoperative risk factors above-mentioned.

Total myocardial revascularization with arterial conduits: radial artery combined with internal thoracic arteries

OBJECTIVE

We prospectively tested the feasibility of achieving total arterial revascularization with the use of the radial artery to revascularize the circumflex, diagonal, and right coronary arteries combined with a left internal thoracic artery graft to the left anterior descending artery and, in some cases, a right internal thoracic artery graft to the right coronary artery.

METHODS

In 164 patients, the radial artery was used as a free Y or T graft from the left internal thoracic artery. Of 568 grafts (3.5 +/- 1 [standard deviation] per patient), 296 (1.8 +/- 0.8 per patient) were constructed with the radial artery as single grafts or as double, triple, or quadruple sequential anastomoses to the circumflex, diagonal, and posterior descending arteries. Diltiazem was administered to prevent spasm. Forty-six patients underwent coronary angiography before discharge from the hospital. Follow-up time was 1 to 19 (9.5 +/- 6.1) months.

RESULTS

Total arterial revascularization was achieved in 137 patients (83.5%). Three (1.8%) died postoperatively of sepsis, ventricular fibrillation, and heart failure, respectively. Three (1.8%) had postoperative myocardial infarction. No hand ischemia occurred. Angiography showed patency of all arterial conduits. Radial artery spasm appeared in 3 (6.5%) of 46 angiograms. Two patients (1.2%) died during the follow-up period of pneumonia and gastrointestinal tract bleeding, respectively. No other events or reoperations occurred, and 95.1% of the patients are free of symptoms.

CONCLUSIONS

The radial artery, as a free Y or T graft from the left internal thoracic artery to the circumflex, diagonal, and right coronary arteries, permits total arterial revascularization with excellent patency rates, minimal morbidity and mortality, and no need for reoperation. Longer follow-up times are necessary to draw definitive conclusions.

Lateral origin of the right internal thoracic artery: report of a case

We report herein the unusual case of a patient in whom postoperative angiography following coronary artery bypass grafting (CABG) revealed a lateral origin of the right internal thoracic artery (ITA) and a normal origin of the left ITA, both of which were demonstrated to be patent and did not follow a tortuous course. The CABG had involved revascularization of the left anterior descending artery (LAD) with the right ITA, and the obtuse marginal artery with the left ITA. The patient had an uneventful postoperative course and developed no respiratory symptoms.

Single versus bilateral internal mammary artery grafts: 10-year outcome analysis

BACKGROUND

The superior long-term patency of the internal mammary artery (IMA) confers important short-term and late survival advantages when grafted to the left anterior descending coronary artery. However, it remains uncertain whether patients derive additional survival benefit when both IMAs are used in coronary revascularization.

METHODS

Between June 1983 and May 1986, 160 patients (mean age 60 years) received bilateral IMA grafts for coronary artery bypass procedures, and in 93% of patients, the right IMA was used to bypass the left coronary system. During a similar interval, a group of 161 patients matched for symptomatic status and extent of disease (mean age, 62 years) received a single left IMA and saphenous vein grafts.

RESULTS

The two groups were similar with respect to gender, preoperative angina class, priority status, extent of coronary artery disease, left ventricular function, and number of distal anastomoses. Diabetes was more prevalent in the patient group receiving a single IMA graft (27% versus 17.5%; p = 0.05). Early outcome was similar in the two groups; operative mortality was 0.6% for the patient group receiving single IMA grafts and 0% for those with bilateral IMA grafts. The mean follow-up of 320 hospital survivors was 10 years. Univariate analysis revealed significantly fewer overall deaths in the patients receiving bilateral IMA grafts (n = 30; p = 0.05), and less late cardiac mortality (n = 12; p = 0.016). Ten-year actuarial survival for patients dismissed from the hospital was 76% for those receiving single IMA graft versus 85% for those receiving bilateral IMA grafts. Multivariate analysis revealed diabetes (risk ratio = 1.73), advancing age (risk ratio = 1.08), and lower ejection fraction (risk ratio = 1.01) to be the only significant predictors of late cardiac death. Use of a single IMA graft was not significant (p = 0.138) despite a risk ratio of 1.78. Use of only a single IMA graft correlated with an increased risk of angina recurrence (p < 0.001), late myocardial infarction (p = 0.019), and risk of any cardiac event (p < 0.001).

CONCLUSIONS

Independent risk factors for late death were diabetes mellitus, older age, and reduced ejection fraction. Patients receiving bilateral IMA grafts had better long-term survival than those with a single IMA graft, but this was not independent of diabetes. Multivariate analysis, however, did confirm that compared with single arterial grafts, bilateral IMA grafting was an independent predictor of lower rates of angina recurrence, late myocardial infarction, and the composite end point of any cardiac event.

Modified T graft for triple-vessel disease

BACKGROUND

Arterial coronary bypass grafts are used in younger patients due to the limited long-term patency of saphenous vein grafts. Using both internal thoracic arteries in a T graft configuration allows complete myocardial revascularization without the need for alternative conduit.

METHODS

A prospective analysis of 75 consecutive patients with triple-vessel disease who were aged less than 66 years and who had a left ventricular ejection fraction greater than 0.50 was performed from November 1994 to November 1995. Seventy-three patients underwent myocardial revascularization using a modified T graft technique using both internal thoracic arteries. Postoperative cardiac enzyme and electrocardiographic analyses were performed along with routine surgical and cardiologic review to March 1996.

RESULTS

There were no deaths or perioperative myocardial infarcts, and there was no sternal dehiscence due to infection. Five patients had recurrent angina and underwent repeat angiography. Three were treated by single coronary artery angioplasty and 2 with medical therapy.

CONCLUSIONS

A modified T graft revascularization of patients selected by the protocol used in this study is safe.

Improved survival with multiple left-sided bilateral internal thoracic artery grafts

BACKGROUND

Although conceptually sound, the use of multiple internal thoracic artery (ITA) bypass grafts to improve long-term clinical results remains controversial. This operation typically involves grafting the left ITA to the anterior descending artery and the right ITA to the right coronary artery. Past clinical studies of bilateral ITA operations have not examined comparative results associated with which coronary arteries received the ITA bypass grafts. Because grafting a superior conduit to an artery of lesser physiologic importance might reduce the clinical benefits, we compared the outcomes of patients receiving different configurations of bilateral ITA operations.

METHODS

The study group was 498 consecutive bilateral ITA operations, constituting the 10-year experience of a single surgeon. Follow-up averaged 7.1 years (mode 7.3 years), and was 94.2% complete. These patients were divided into two groups, 311 patients (group I) who underwent the traditional operation (left ITA to the left anterior descending artery, right ITA to the right coronary artery), and 187 patients (group II) who received revascularization of branches of the left coronary artery (left ITA to the circumflex system and right ITA to the left anterior descending artery).

RESULTS

The study groups were similar in age, severity of disease, number of bypassed arteries, ejection fraction, diabetes, hypertension, and duration of operation. There were more male patients in group II (91.4% versus 82.3%). A multivariate analysis showed that the location of ITA bypass grafts influenced survival independent of gender (p = 0.0288). Operative morbidity and mortality were similar between groups. Ninety-three patients had repeat angiography with equivalent patency rates of the ITA conduits (91.7% versus 89.6%; p = 0.67). The Kaplan-Meier actuarial survival estimate demonstrated a significant improvement in survival of patients in group II who received both ITA bypass grafts to left-sided arteries (p = 0.021), with the survival curves diverging at 6 years. More patients in group II were in New York Heart Association class I or II, but the difference was not statistically significant (94.6% versus 91.6%). Only 2 patients required reoperation.

CONCLUSIONS

It appears that maximum long-term benefit from bilateral ITA operations is achieved by grafting the ITA conduits to coronary arteries that supply more left ventricular muscle.

Suitability and durability of multiple internal thoracic artery coronary artery bypasses

OBJECTIVE

The authors evaluate operative and extended outcomes of coronary artery bypass surgery using the bilateral internal thoracic arteries (ITAs) as bypass grafts. The authors conclude that the procedure is viable and of long-term benefit to most patients.

SUMMARY BACKGROUND DATA

Multiple ITA grafting was met with early enthusiasm by the surgical profession, but skepticism and controversy arose with reports of increased operative morbidity, insufficient graft blood flow, a high incidence of failure of the right ITA, and uncertainty about durability and long-term benefits.

METHODS

To assess the actual incidence and impact of these complications and long-term results, the authors prospectively studied 500 consecutive patients with multiple ITA bypasses, constituting the closely observed and carefully documented experience of one surgeon over an 11-year period.

RESULTS

Operative mortality in the series of 500 patients was 1.8%, perioperative myocardial infarction (new Q wave) rate was 0.6%, and deep sternal wound infection occurred in 1%. Six patients (1.2%) had strokes, and nine patients (1.8%) were returned to the operating room to control bleeding. One hundred ninety-eight patients who had abnormal stress test results before surgery were retested within 3 months of surgery. Ninety-four percent of these were normal, 3% were nondiagnostic, and 3% were abnormal. After a mean follow-up of 7.1 years (mode, 7.2 years), 87.5% of patients in the sample were alive, and 93.2% of this group have experienced continuing good clinical results (New York Heart Association class I or II). Eighty-nine patients who underwent an angiogram had 90.8% patency rates of ITA bypasses and 84.5% patency of vein grafts. Only two patients required repeat operations.

CONCLUSIONS

The operative results did not support the contention that the coronary artery bypass using ITA procedure produces higher than acceptable mortality and morbidity rates. Multiple ITA bypasses can be performed without excessive morbidity, with low reoperation rates and long-term outcomes that should encourage skeptics to reconsider the procedure's clinical value.

Early Results with Bilateral and Single Internal Mammary Artery Grafts. Are They Different?

Between June 1991 and June 1996, 391 patients underwent isolated myocardial revascularization using bilateral internal mammary artery. Three hundred and sixty-five of these patients could be matched retrospectively on the basis of preoperative characteristics with 365 patients operated on during same period who had left internal mammary artery as a single or sequential graft with additional vein grafts. The cardiopulmonary bypass times and aortic cross-clamp times were similar in both groups. There were no statistically significant differences in the two groups in terms of operative mortality (0.55% versus 0.82%), perioperative myocardial infarction (2.46% versus 2.19%), low cardiac output (1.64% versus 1.09%), reexplorations (1.10% versus 1.92%), wound complications (1.10% versus 2.46%), length of stay in the intensive care unit, and total hospital stay. The incidence of respiratory, central nervous system, and renal complications showed no difference between the two groups. Logistic regression analysis showed that the number of internal mammary artery grafts was not a predictor for perioperative complications. If better long-term event-free survival is associated with the use of bilateral internal mammary artery, it should be used wherever possible.

Total arterial revascularization of the heart: intentional or inevitable

The impact of left internal mammary to left anterior descending coronary bypass grafting in enhancing long-term patient survival has led to a widespread interest in arterial grafting over the past decade. It is now accepted that the internal mammary artery is a biologically superior coronary bypass graft compared with the traditional saphenous vein. Experience with other arterial grafts--the right gastro-epiploic artery, the inferior epigastric artery and the radial artery--has shown compelling evidence that they share the same biologic advantage. With the judicious use of some or all of these conduits, all regions of the heart can be reached, and total arterial revascularization is a feasible and desirable objective on a routine basis. As long-term results become available, it is inevitable that it will become the operation of choice.

Port-access bilateral internal mammary artery grafting for left main coronary artery disease: canine feasibility study

BACKGROUND

To extend the applications of minimal access cardiac surgery, an endovascular cardiopulmonary bypass (CPB) system that allows cardioplegia delivery and cardiac venting was used to perform bilateral internal mammary artery (IMA) bypass grafting in six dogs.

METHODS

The left IMA (LIMA) was taken down thoracoscopically from three left lateral chest ports, followed by the right IMA (RIMA) from the right side. One left-sided port was extended medially 5 cm with or without rib resection, to expose the pericardium. Both IMAs were divided and exteriorized through the left anterior mediastinotomy. Flow and pedicle length were satisfactory in all cases. Femoral-femoral bypass was used and the heart arrested with antegrade delivery of cardioplegic solution via the central lumen of a balloon catheter inflated to occlude the ascending aorta. All anastomoses were made through the mediastinotomy under direct vision. In five studies the RIMA was attached to the left anterior descending artery (LAD) and the LIMA to the circumflex, and in one study the RIMA was tunneled through the transverse sinus to the circumflex and the LIMA was anastomosed to the LAD. All animals were weaned from CPB in sinus rhythm without inotropes. CPB duration was 108 +/- 27 minutes (mean +/- SD) and the clamp duration was 54 +/- 10 minutes.

RESULTS

Preoperative and postoperative cardiac outputs were 2.9 +/- 0.71/min and 2.4 +/- 0.31/min, respectively (p = NS), and corresponding pulmonary artery occlusion pressures were 6 +/- 3 mmHg and 7 +/- 2 mmHg, respectively (p = NS). All 12 grafts were demonstrated to be fully patent. Postmortem examination revealed well aligned pedicles and correctly grafted target vessels.

CONCLUSION

This canine model demonstrates the potential for a less invasive approach to the surgical management of left main coronary artery disease in humans.

Operation for two-vessel coronary artery disease: midterm results of bilateral ITA grafting versus unilateral ITA and saphenous vein grafting

BACKGROUND

Several studies have demonstrated that single internal thoracic artery (ITA) grafting achieves better results than the use of vein grafts alone, but it is less clear whether bilateral ITA grafting produces better long-term results than a single ITA graft to the left descending coronary artery does.

METHODS

We analyzed the early and midterm results of the surgical treatment of two-vessel coronary artery disease (left anterior descending artery and right coronary artery) in two groups of 80 consecutive patients operated on between 1985 and 1989 who received either a bilateral ITA graft or a unilateral ITA graft combined with a saphenous vein graft. Patients were selected from a data base so as to be rigorously matched for demographic and clinical factors as well as angiographic variables, with the researcher being blinded to any additional intraoperative or postoperative data. Follow-up examination was performed after a mean postoperative interval of 8 years.

RESULTS

Univariate analysis showed a somewhat higher incidence of sternal complications in the bilateral ITA group (4.8% versus 1.2%; p < 0.02) and a significantly lower reintervention-free survival at 8 years in the group of patients who received a unilateral ITA and saphenous vein graft (84% +/- 5.5% versus 95% +/- 1.5%; p < 0.02). The latter was predominantly due to the development of significant main stem lesions necessitating a redo procedure during the follow-up interval or to the need for percutaneous coronary angioplasty of circumflex artery lesions that were not critical at the time of the initial operation. Perioperative risk was similar in both groups of patients. Old age and a history of congestive heart failure were the most important predictors of perioperative mortality and morbidity for patients receiving bilateral ITAs. Multivariate analysis did not demonstrate any benefit from bilateral arterial grafting over unilateral ITA bypass combined with saphenous vein grafting in terms of overall survival and event-free and intervention-free survival.

CONCLUSIONS

Although bilateral ITA grafting can be performed with a perioperative risk comparable with that for unilateral ITA and saphenous vein grafting, long-term results (up to 8 years) of surgically treated two-vessel coronary artery disease are not improved by bilateral ITA grafting.

Routine use of unilateral and bilateral radial arteries for coronary artery bypass graft surgery

OBJECTIVES

This study sought to evaluate the routine use of radial artery (RA) grafts in patients undergoing coronary artery revascularization.

BACKGROUND

Previous long-term studies have documented poor patency of saphenous vein grafts compared with internal thoracic artery (ITA) grafts.

METHODS

We performed a prospective review of 175 of 249 consecutive patients.

RESULTS

Fifty-four patients had bilateral RAs harvested. Mean number (+/- SD) of grafts/patient was 3.27 +/- 0.93, with 2.76 +/- 0.97 arterial grafts; a mean of 1.53 +/- 0.68 grafts were performed with the RA. The operative mortality rate was 1.6%. No deaths were related to RA grafts, and there were no RA harvest site hematomas or infections. Transient dysesthesia 1 day to 4 weeks in duration occurred in the distribution of the lateral antebrachial cutaneous nerve in six extremities (2.6%). Elective cardiac catheterization in 60 patients at 12 weeks postoperatively demonstrated a 95.7% patency rate.

CONCLUSIONS

Because of potential benefit of long-term patency associated with arterial grafts, minimal morbidity and mortality associated with use of the RA and excellent short-term patency rates, we cautiously recommend use of one or both RAs as additional conduits to be used concomitantly with the ITA for arterial revascularization of the coronary arteries.

Coronary bypass graft fate and patient outcome: angiographic follow-up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years

OBJECTIVES

We sought to examine, angiographically, the longterm fate of a large number of mainly venous coronary bypass grafts and to correlate graft patency and disease with patient survival and reoperation.

BACKGROUND

Much is known about bypass graft patency and disease, but the precise relation between graft fate and patient outcome has not been substantiated and documented.

METHODS

A total of 1,388 patients underwent a first coronary artery bypass graft procedure at a mean age of 48.9 years, 234 had a second bypass procedure at a mean age of 53.3 years, and 15 had a third bypass procedure at a mean age of 58.2 years during the 25-year period from 1969 to 1994. Most were male military personnel or veterans; 12% were < or = 39 years old. Of 5,284 grafts placed, 91% were venous and 9% arterial. Angiograms were performed on 5,065 (98% of surviving) grafts early, on 3,993 grafts at 1 year and on 1,978 grafts at 5 years after operation; other examinations were also performed up to 22.5 years after operation, and 353 grafts were examined after > or = 15 years. Grafts were graded for patency and disease. The status of all patients was known at the study's end.

RESULTS

The perioperative mortality rate was 1.4% for an isolated first coronary bypass procedure, 6.6% for reoperation. Vein graft patency was 88% early, 81% at 1 year, 75% at 5 years and 50% at > or = 15 years; when suboptimal grafts, graded B, were excluded from calculation, the proportion of excellent grafts, graded A, decreased to 40% after > or = 12.5 years. After the early study, the vein graft occlusion rate was 2.1%/year. Internal mammary artery graft patency was significantly better but decreased with time. Vein graft disease appeared by 1 year and the rate accelerated by > or = 2.5 years, involving 48% of grafts at 5 years and 81% at > or = 15 years; 44% of the latter grafts were narrowed > 50%. Survival of all patients was 93.6% at 5 years. 81.1% at 10 years, 62.1% at 15 years, 46.7% (150 patients) at 20 years and 38.4% (25 patients) at 23 years after operation. Survival decreased as age increased, but curves approximated "normal" life expectancy for older patients. Survival curves at all ages showed a steeper decline after 7 years. The rate of reoperation increased between 5 years and 10 to 14 years, then decreased to stable levels. Coronary atheroembolism from vein grafts was the major cause of morbidity and mortality associated with reoperation. Vein graft patency and disease were temporally and closely related to reoperation and survival.

CONCLUSIONS

Coronary bypass graft disease and occlusion are common after coronary artery bypass grafting and increase with time. They are major determinants of clinical prognosis, specifically measured by reoperation rate and survival. Intraoperative graft atheroembolism was a major reoperation hazard. Reoperation is definitely worthwhile but entails identifiable risks that must be dealt with.

Bilateral internal mammary artery grafting in women: a 21-year experience

BACKGROUND

Coronary artery bypass grafting traditionally has carried a higher mortality rate in women than in men. It remains the leading cause of death in women despite major advances in diagnosis and treatment over the past 2 decades.

METHODS

A retrospective analysis was conducted to identify risk factors that adversely influence hospital mortality, morbidity, and long-term clinical results in women undergoing bilateral internal mammary artery grafting. From January 1972 through October 1994, 327 consecutive women received bilateral internal mammary artery grafts and supplemental vein grafts. Patient age ranged from 32 to 84 years (mean, 65.7 years). There were 262 patients (80.1%) with three-vessel disease; 71 (21.7%) had substantial (> 50%) stenosis of the left main coronary artery, 65 (19.9%) had a moderately reduced (0.30 to 0.50) ejection fraction, and 11 (3.4%) had a severely reduced (< 0.30) ejection fraction. Preoperatively, 316 patients (96.6%) were in New York Heart Association class III or IV.

RESULTS

There were 1,016 coronary artery grafts (mean, 3.1 per patient). The overall hospital mortality rate was 3.4% (11 of 327). Postoperative complications included myocardial infarction in 18 patients (5.5%), stroke in 5 (1.5%), pulmonary insufficiency in 11 (3.4%), reoperation for bleeding in 7 (2.1%), and sternal infection in 8 (2.4%). Independent predictors of operative death were postoperative cardiac arrest (p < 0.001), use of intraaortic balloon pump (p < 0.001), and reoperation for bleeding (p < 0.050). Follow-up was completed on 316 hospital survivors (100%) and ranged from 6 months to 21 years (mean, 5.1 years). Actuarial survival (mean +/- standard error of the mean) was 90.5% +/- 1.9% at 5 years and 65.6% +/- 6.1% at 10 years. At follow-up, 252 patients (94.0%) were asymptomatic in New York Heart Association class I, and 12 (4.5%) were in class II.

CONCLUSIONS

This longitudinal study demonstrates that bilateral internal mammary artery grafting, though technically demanding, can be achieved in women with low hospital mortality and morbidity rates. Patients experienced reduced late cardiac events, excellent functional improvement, and enhanced long-term survival.

Right internal thoracic artery through the transverse sinus in myocardial revascularization

BACKGROUND

This study presents the late patency rate of the right internal thoracic artery (ITA) used in situ through the pericardium transverse sinus to the circumflex artery and its branches.

METHODS

From April 1983 to December 1994, 2,642 patients were submitted to myocardial revascularization; 201 of them had bilateral ITAs. The right ITA through the transverse sinus was grafted to obtuse marginal artery in 170 patients (84.5%) and the left ITA was grafted to the anterior descending artery in 188 patients (93.5%). Angiographic studies were performed in 80 patients, 44 patients in the immediate postoperative period and 36 patients in the late follow-up (mean, 51.6 months).

RESULTS

The right ITA was patent in 75 patients (93.7%) and the left ITA was patent in 77 (96.2%). At the late postoperative period, the right ITA was patent in 33 patients (91.6%) and the left ITA was patent in 34 (94.4%).

CONCLUSIONS

The right ITA placed through the pericardium transverse sinus has a good long-term patency rate, similar to that observed with the left ITA and superior to that of saphenous vein grafts for myocardial revascularization.

Risk factors for deep sternal wound infection after sternotomy: a prospective, multicenter study

Several risk factors for deep sternal wound infection after sternotomy remain unclear. To assess and compare risk factors among units, a prospective study included 1830 patients in 10 units during a 4-month period: 960 underwent coronary artery bypass grafting and 870 underwent other procedures. According to the Centers for Disease Control and Prevention definitions, 2.3% of patients (42/1830) acquired a deep sternal wound infection. Independent risk factors for deep sternal wound infection were obesity, coronary artery bypass grafting, reoperation, and postoperative inotropic support. Independent risk factors after coronary artery bypass grafting were obesity, bilateral internal thoracic artery grafting, reoperation, and postoperative inotropic support. In all five of the units usually performing bilateral internal thoracic artery graftings, this procedure was associated with high risk of deep sternal wound infection. Duration of operation was a major risk factor in comparison of the unit with the highest risk of deep sternal wound infection with the other nine units; this suggests that parameters related to the perioperative period were involved. Multicenter surveillance is useful to determine reliable risk factors for deep sternal wound infection, to define a high-risk population before operation, and to assess unit-specific risk factors.

Early postoperative angiographic assessment of radial grafts used for coronary artery bypass grafting

Despite a revival of interest in using the radial artery as an alternative conduit for myocardial revascularization, little angiographic documentation of early postoperative results has been presented, particularly in North America. Accordingly, 60 of 150 patients who underwent coronary artery bypass with radial arteries from November 1993 to July 1995 have had postoperative cardiac catheterization at our institution. The patency rate of the radial artery grafts was 95.7% (90 of 94 grafts patent) with an average internal diameter of 2.51 mm. Four radial artery grafts showed diffuse narrowing. The patency rate of the internal thoracic artery grafts was 100% with an average internal diameter of 2.25 mm. Three of 62 grafts demonstrated diffuse narrowing. Two of 24 (7.7%) saphenous vein grafts were occluded; the average internal diameter was 3.23 mm. The internal thoracic artery, the radial artery, and saphenous vein grafts were, respectively, 7.5%, 19.5%, and 53.3% larger than the anastomosed native coronary arteries. Graft-dependent flow was found in 81.1% of the radial artery grafts.

CONCLUSION

The results of this study demonstrate that the short-term patency rate of radial artery grafts is excellent.

Bilateral and unilateral use of internal thoracic artery for myocardial revascularization. Comparison of extubation outcome and duration of hospital stay

The left internal thoracic artery is usually used as arterial conduit for myocardial revascularization; however, there is an increasing popularity of bilateral use of this artery for grafting. We examined 180 patients with both types of arterial conduits to answer whether bilateral use of the internal thoracic artery makes the difference in postoperative extubation outcome and duration of hospital stay in comparison to the unilateral use of this conduit. Ninety-three patients with bilateral conduit and 87 patients with unilateral conduit, with comparable age, cardiopulmonary bypass, and aortic cross-clamp time have been studied. On the basis of statistical and retrospective analysis, we conclude that bilateral use of internal thoracic artery for myocardial revascularization prolongs required postoperative respiratory support (12.0 h against 7.6 h) not affecting the duration of the mean hospital stay.

Skeletonized and pedicled internal thoracic artery grafts: effect on free flow during bypass

BACKGROUND

The skeletonization technique of the internal thoracic artery (ITA) is used as a dissection technique for myocardial revascularization procedures. This study compared free flow between skeletonized ITA grafts and ITA pedicled grafts.

METHODS

The ITA pedicled grafts were sprayed and wrapped in sponges soaked in dilute papaverine solution in 14 patients and prepared with intraluminal papaverine injection in 18 patients. For 23 other patients, the ITA was skeletonized. We measured the first free flow from the distal ITA early after the start of cardiopulmonary bypass and the second free flow just before the ITA was grafted to the left anterior descending artery.

RESULTS

The first flow was greater in the skeletonized ITAs than in the ITA pedicled grafts with topical application of papaverine alone (38.9 +/- 15.8 versus 18.0 +/- 6.8 mL/min; p < 0.001). For the second flow, the pedicle grafts with intraluminal papaverine injection and the skeletonized ITAs showed greater flow rate than the pedicled grafts with topical application of papaverine (67.4 +/- 25.5 and 59.7 +/- 22.5 versus 38.1 +/- 13.1 mL/min; p < 0.005 and p < 0.05, respectively), but there was no significant difference between the former two groups (p = 0.53).

CONCLUSIONS

Skeletonization of the ITA is as efficient a strategy to increase the flow as intraluminal papaverine injection for the ITA pedicled graft. When the ITA is harvested in a skeletonized fashion, arterial spasm and reduced early flow can be avoided, even without intraluminal injection of papaverine.

Coronary bypass surgery with internal-thoracic-artery grafts--effects on survival over a 15-year period

BACKGROUND

Aortocoronary bypass surgery has been performed most often with the patient's saphenous vein as the conduit. The internal-thoracic-artery graft, which has superior patency rates, has been shown to have clinical advantages, but it is not known how long these advantages persist.

METHODS

We identified all the patients in the registry of the Coronary Artery Surgery Study who had undergone first-time coronary-artery bypass grafting. Those with internal-thoracic-artery bypass grafts (749 patients) were compared with those with saphenous-vein bypass grafts only (4888 patients) with respect to survival over a 15-year follow-up period.

RESULTS

In a multivariate analysis to account for differences between the two groups, the presence of an internal-thoracic-artery graft was an independent predictor of improved survival and was associated with a relative risk of dying of 0.73 (95 percent confidence interval, 0.64 to 0.83). This improved survival was also observed in subgroups including patients 65 years of age or older, both men and women, and patients with impaired ventricular function. The survival curves of the two groups showed further separation over the years of follow-up, with a more marked downsloping after eight years in the curve for the group with saphenous-vein grafts only than in that for the group with internal-thoracic-artery grafts.

CONCLUSIONS

As compared with saphenous-vein coronary bypass grafts, internal-thoracic-artery grafts conferred a survival advantage throughout a 15-year follow-up period. The survival advantage increased with time, suggesting that the initial selection of the conduit was a more important factor in survival than problems appearing long after surgery, such as the progression of coronary disease.

The current status of myocardial revascularization: changing trends and risk factor analysis

From November 1989 to December 1994, we performed 2264 bypass procedures. Data were collected prospectively. The population was divided into three subgroups: group 1 = single internal mammary artery (IMA) +/- veins (n = 1584); group 2 = veins only (n = 503); and group 3 = two or more arterial conduits +/- veins (n = 177). Patients who received only saphenous vein conduits (group 2) were significantly older (66.7 +/- 8.9 years) than either group 1 (60.3 +/- 8.3 years) or group 3 (51.6 +/- 9.2 years). Furthermore, this cohort group had the highest percentage of females (28.6%), urgent cases (43.5%), preoperative myocardial infarction (MI) (18.5%), and redo surgery (5.4%). In contrast, patients who received two or more arterial conduits were 94.9% male, and had the lowest incidence of urgent cases (18.1%) and redo surgery (0.5%). Mortality was 1.4% in group 1 and 3.2% in group 2; there were no deaths in group 3. Furthermore, group 2 patients had the highest incidence of perioperative MI (6.6%), low output syndrome (22.1%), intra-aortic balloon pump (IABP) assist (6.2%), and stroke (2.7%). By multivariate logistic regression analysis (odds ratio in parentheses), redo surgery (7.92), preoperative IABP (5.53), poor LV function (4.01), renal impairment (3.94), and advanced age (2.12) were all predictors of operative mortality. When mortality and morbidity (death, infarction, low output syndrome, IABP assist) were combined, regression analysis revealed that in addition to the above variables, female gender and cold cardioplegia were also independent predictors of combined mortality and morbidity. Resource utilization was determined for the three patient groups. There was concern that the increased technical demands of multiple arterial grafting along with longer periods of aortic occlusion and pump times may lead to increased complications and prolonged hospital stay. However, we found that group 3 had the lowest ventilation time, intensive care unit stay, and hospital stay. The results no doubt were influenced by case selection. Whether or not this approach to revascularization will increase long-term survival and freedom from reoperation will require further study.

Unilateral versus bilateral internal mammary revascularization. Survival and event-free performance

BACKGROUND

The influence of unilateral (UL) and bilateral (BL) mammary artery revascularization, within age groups < or = 60 years and > 60 years, on patient survival, ischemic-related events, and interventional management was studied in 1142 patients who had coronary artery bypass graft surgery between 1984 and 1992.

METHODS AND RESULTS

UL revascularization was performed in 765 (67%) and BL in 377 (33%) patients with supplemental vein grafts. The overall early and hospital mortality rate was 2.7%. For UL in the age group < or = 60 years, it was 1.1%; for BL < or = 60 years, 1.3% (P = NS); for UL > 60 years, 4.3%; and for BL > 60 years, 2.8% (P = NS). Twenty-five preoperative patient characteristics representing demographics, extent of disease, concomitant disease, ventricular dysfunction, previous surgery, and status did not differentiate the patient groups (P = NS). Patient survival at 5 years was not different: 94% for UL < or = 60 years, 95% for BL < or = 60 years, 91% for UL > 60 years, and 86% for BL > 60 years (P = NS). The freedom from ischemic-related events was not different at 5 years (P = NS). The freedom from recurrent angina was 78% for UL < or = 60 years, 88% for BL < or = 60 years, 82% for UL > 60 years, and 83% for BL > 60 years (P = NS). The myocardial infarction freedom was 98% for UL < or = 60 years, 96% for BL < or = 60 years, 99% for UL > 60 years, and 97% for BL > 60 years (P = NS). The freedom from sudden unexpected death and cardiac death did not differentiate the groups (P = NS). The freedom from angioplasty and reoperation did not differentiate the groups (P = NS). The freedom from all ischemic-related and interventional events was 76% for UL < or = 60 years, 84% for BL < or = 60 years, 81% for UL > 60 years, and 79% for BL > 60 years (P = NS). A trend exists for less angina pectoris in the bilateral population < or = 60 years, which reflects in the trend in the freedom from overall events.

CONCLUSIONS

UL and BL mammary artery revascularizations have the same early mortality regardless of age but do not reveal any advantage for BL revascularization at 5 to 7 years.

Right gastroepiploic-to-coronary artery bypass. The first decade of use

BACKGROUND

The right gastroepiploic artery was first used by us as a coronary artery bypass graft (CABG) in June 1984 and has become an accepted alternative conduit for myocardial revascularization.

METHODS AND RESULTS

We have now performed this operation in 126 patients (111 of whom were men) aged 32 to 78 years. The right gastroepiploic artery was used as a pedicle graft to the right main coronary artery in 25 patients, to its posterior descending branch in 90, to a left ventricular branch in 2, to branches of the circumflex system in 6, and to the left anterior descending artery in 1. Free (aortocoronary) gastroepiploic grafts were placed to circumflex branches in 2 patients. There were 2 hospital deaths (stroke, arrhythmia), and mean +/- SD postoperative stay was 7.5 +/- 2.0 days. All survivors were symptomatically improved and are functionally in New York Heart Association functional class I or II. There have been 3 late deaths (at 34, 50, and 84 months) in 2 to 120 months of follow-up (mean, 41.4 months). Angiography of bypass grafts and coronary arteries was performed in 44 patients at 7 days to 80 months postoperatively, providing direct evidence of gastroepiploic graft patency in 34 patients and strong indirect evidence in another 6; adequate data could not be obtained in 3 patients for technical reasons, and 1 graft was occluded.

CONCLUSIONS

These short-term, intermediate, and long-term results demonstrate the suitability of the right gastroepiploic artery as a CABG. The use of the right gastroepiploic artery as a graft to coronary arteries on the posterior wall of the heart, in conjunction with one or both internal mammary arteries, has the potential to allow complete myocardial revascularization with viable arterial grafts.

Patency of cryopreserved saphenous vein grafts as conduits for coronary artery bypass surgery

STUDY OBJECTIVE

To determine the angiographic patency of cryopreserved saphenous vein grafts used as conduits during coronary artery bypass surgery and whether this is affected by postoperative immunosuppressive therapy.

DESIGN AND SETTING

A retrospective review of medical records and coronary angiograms of patients at a university hospital.

PATIENTS

Eleven patients undergoing 12 coronary artery bypass operations during which a total of 26 distal coronary anastomoses were created using cryopreserved vein grafts.

MEASUREMENTS

Eight postoperative coronary angiograms were performed in 10 patients surviving longer than 1 week. All angiograms were performed on the basis of symptoms of suspected myocardial ischemia. Angiographic results, postoperative anticoagulation, and therapy with immunosuppressive agents were analyzed.

RESULTS

Seventeen cryopreserved vein grafts were studied; one (6%) was patent, 12 (71%) were occluded, and 4 (23%) were stenosed. In patients treated with azathioprine, seven of the eight cryopreserved vein grafts were occluded. In patients not receiving immunosuppression, five were occluded, three were stenosed, and one was patent. All internal mammary grafts were widely patent.

CONCLUSION

Cryopreserved vein grafts have a poor angiographic patency which did not appear to be affected by immunosuppressive therapy with azathioprine. The use of this graft should be restricted and alternative arterial conduits utilized.

Dilation of the internal mammary artery by external and intraluminal papaverine application

Three methods for prevention of perioperative spasm of the internal mammary artery were compared in 78 patients undergoing coronary artery bypass grafting. In group 1, internal mammary artery pedicles were divided distally, clamped, and placed under the upper sternum submerged in papaverine solution (1.5 mg/ml). In group 2, as in group 1 but before clamping, 2 ml of heparinized blood with 1.5 mg/ml papaverine added was injected into the vessel lumen. In group 3 treatment was as in group 2, but heparinized blood with papaverine was injected a second time just before extracorporeal bypass was begun. In a univariate analysis free flow from dilated internal mammary arteries was not significantly different among the groups (group 1, 58 ml/min; group 2, 82 ml/min; group 3, 68 ml/min; p < 0.1). When free flow from dilated internal mammary arteries was the dependent variable in a regression analysis, the use of intraluminal papaverine, high blood pressure during flow measurement, and high initial blood flow were predictors of high flow (all p < 0.01). Morphometric measurements on the resected distal portion of the dilated internal mammary arteries disclosed less folding of the internal elastic lamina and a larger luminal area in groups 2 and 3 compared with respective findings in group 1 (1.21 mm2 and 1.42 mm2 versus 0.77 mm2; p < 0.02). Mechanical vessel wall injury occurred in 8 of 52 internal mammary arteries treated with intraluminal papaverine. Intraluminal papaverine solution injected once or twice in addition to external papaverine exposure therefore provides a better blood flow rate and distal dilation than mere submersion in papaverine solution, but at a considerable risk of mechanical wall injury.

Radial artery and inferior epigastric artery in composite grafts: improved midterm angiographic results

BACKGROUND

The improving results with use of the radial artery and the inferior epigastric artery as coronary bypass conduits were analyzed to assess the suitability of these arteries for myocardial revascularization.

METHODS

Both arteries were used in composite arterial conduits with an internal mammary artery as the blood source. The proximal anastomosis was always constructed before the initiation of cardiopulmonary bypass. From October 1991 to January 1995, 240 patients underwent myocardial revascularization using 163 radial arteries and 124 inferior epigastric arteries with one (224 instances) or both (two instances) internal mammary arteries as inflow conduits. Twenty-five saphenous veins were concomitantly used. There were 208 men and 32 women with a mean age of 60.8 +/- 8.6 years (range, 28 to 80 years). In 73 patients (30.4%), the operation was performed on an urgent basis, and in 11 (4.6%), it was a repeat operation. The mean left ventricular ejection fraction was 0.55 +/- 0.12, and in 21 patients (8.8%), it was less than 0.35. Of 681 distal anastomoses, 188 were constructed using the radial artery (35 double and one triple sequential anastomosis) and 125, using the inferior epigastric artery (one double sequential anastomosis). A mean of 3.0 arterial anastomoses per patient were constructed (3.1 anastomoses/patient including saphenous veins). Six patients (2.5%) underwent associated procedures: aortic valve replacement (2), carotid endarterectomy (2), mitral valve replacement (1), and aortic valve and ascending aorta replacement (1). Most of the inferior epigastric arteries were grafted on diagonal branches and most of the radial arteries, the circumflex territory.

RESULTS

No deaths occurred in the operating room. Three patients (1.3%) died postoperatively, and 2 patients (0.8%) died 6 months after operation. At a mean follow-up of 18.5 +/- 10.4 months (range, 1 to 39 months), 227 patients (96.6%) were asymptomatic. The cumulative patency rate of the radial artery grafts was 93.1% and of the inferior epigastric artery grafts, 95.7%.

CONCLUSIONS

Our data suggest that use of the RA and the IEA in composite conduits for myocardial revascularization is feasible. These arteries can be safely used when bilateral internal mammary artery or sequential internal mammary artery grafting is not advisable.

Late endothelial function of free and pedicled internal mammary artery grafts

The internal mammary artery has greater long-term patency than the saphenous vein when used for coronary bypass grafting. Therefore, bilateral use of the internal mammary artery for grafting with the right internal mammary artery used as a "free" graft may result in improved graft survival. The study objectives were to compare the endothelial-dependent and -independent vasodilatory response in free and pedicled internal mammary artery grafts in patients who had previously undergone coronary surgery. Free (group 1, n = 8) and pedicled (group 2, n = 7) internal mammary artery grafts were studied by comparing the response to selective infusion of the endothelial-dependent vasodilator substance P (1.4 up to 22.4 pmol/min in doubling dose increments) followed by isosorbide dinitrate (2 mg over 2 minutes), in patients undergoing coronary angiography, 1 month to 6 years after coronary surgery. Maximal dilatory response to substance P was 8.7% +/- 1.8% in pedicled grafts compared with 8.8% +/- 2.3% in free grafts (p = not significant), with the dose response for both groups being similar. Infusion of isosorbide dinitrate produced only minimal further dilatation in both groups. No significant difference was found in endothelium-dependent and -independent vasodilatory response between free and pedicled internal mammary artery grafts, suggesting that the use of the free right internal mammary artery and other arterial grafts may enhance graft survival.

Right Gastroepiploic Artery in Myocardial Revascularization: Portuguese Experience

Excellent results obtained with the use of the internal mammary artery in myocardial revascularization led us to complement its use with other arterial conduits, and the right gastroepiploic artery (RGEA) emerged as a valid alternative, allowing the expansion of total arterial revascularization. From July 1988 until September 1994 we utilized the RGEA in 101 patients with ages between 30 and 71 years (mean 54 9.43). The RGEA was used to bypass the posterior descending artery in 90 patients and for the marginal branches of the circumflex in 11. Exclusive arterial revascularization was possible in 92% of the cases with a mean of 2.7 bypasses per patient. There were 4 (4%) cases of death, and 3 instances of perioperative myocardial infarction. Angiographic control of the RGEA performed in 46 patients showed a patency of 87%. In conclusion, the RGEA was predominantly used to revascularize the inferior wall of the myocardium as a complement to the internal mammary artery. Its use occurred without significant morbidity and mortality, and postoperative angiographic visualization of these arterial conduits allowed us to expect good mid-and long-term patency.

Genetic engineering of vein grafts resistant to atherosclerosis

Previously, researchers have speculated that genetic engineering can improve the long-term function of vascular grafts which are prone to atherosclerosis and occlusion. In this study, we demonstrated that an intraoperative gene therapy approach using antisense oligodeoxynucleotide blockage of medial smooth muscle cell proliferation can prevent the accelerated atherosclerosis that is responsible for autologous vein graft failure. Selective blockade of the expression of genes for two cell cycle regulatory proteins, proliferating cell nuclear antigen and cell division cycle 2 kinase, was achieved in the smooth muscle cells of rabbit jugular veins grafted into the carotid arteries. This alteration of gene expression successfully redirected vein graft biology away from neointimal hyperplasia and toward medial hypertrophy, yielding conduits that more closely resembled normal arteries. More importantly, these genetically engineered grafts proved resistant to diet-induced atherosclerosis. These findings establish the feasibility of developing genetically engineered bioprostheses that are resistant to failure and better suited to the long-term treatment of occlusive vascular disease.

Risk and results of bypass grafting using bilateral internal mammary and right gastroepiploic arteries

From January 1990 to June 1994, 240 patients (mean age, 60 +/- 10 years) underwent myocardial revascularization with the exclusive use of in situ bilateral internal mammary and right gastroepiploic arteries. Left ventricular function was normal in 34% of patients, moderately impaired in 58.5%, and severely impaired in 7.5%. The mean number of distal anastomoses was 3.5 +/- 0.7 and the rate of complete myocardial revascularization was 80%. Early mortality was 0.4%, and complications occurred in 20 patients: myocardial infarction, 1.6%; intraaortic balloon pump, 0.8%; reoperation for bleeding, 0.8%; and mediastinitis, 0.4%. Early (15th postoperative day) angiographic control of grafts was performed in 51 patients; the rate of functional and patent anastomoses was 100% for internal mammary arteries and 96% for gastroepiploic arteries. Early functional results (3 +/- 1 postoperative months) were studied in 141 patients during exercise test with medical treatment: 99% were symptom-free and 14% had ischemic modification of electrocardiograms. A 2-year postoperative functional assessment without medical treatment was performed during exercise test in 66 patients: 98% were symptom-free and 26% had ischemic modification of electrocardiograms; during the same procedure, thallium myocardial scintigraphy was obtained in 50 patients and 18 patients had moderate ischemic defect on exercise. Ischemic modifications of electrocardiograms and defects seen on thallium scintigraphy were correlated significantly with incomplete revascularization (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary revascularization with the radial artery: new interest for an old conduit

Between July 1992 and May 1994, 148 patients (18 females) underwent myocardial revascularization with a radial artery (RA) graft. The left RA was used in 97.3% of cases. All but two patients received at least one additional arterial conduit: 137 left and 59 right internal mammary arteries (IMA); 23 inferior epigastric arteries; and 21 right gastroepiploic arteries. Total arterial revascularization was achieved in 127 patients (85.8%). An average of 3.0 anastomoses/patient were constructed, 2.8 of which were arterial. RA proximal anastomoses were placed on the IMA in 75% of cases, while direct anastomosis to the aorta (23.7%) or to a saphenous vein (1.3%) was performed in the remainder. When anastomosed to an IMA, the RA was subsequently infused intraluminally with 10 mg of papaverine (1 mg/mL). The target artery was the left anterior descending or one of its branches in 14.7% of cases, the circumflex system in 76.3%, and the native right coronary or one of its branches in the remaining 9%. An infusion of diltiazem (4 mg/hour) was started once the aorta was unclamped, and patients were maintained on oral diltiazem for 6 months postoperatively. Operative mortality was 1.4% (2 patients), with the additional late deaths from noncardiac causes. In one patient there was a prolonged serous drainage from the RA donor site. Of the 144 survivors 140 are asymptomatic. Follow-up angiography demonstrated 100% early patency (< 30 days, 41 patients), and 94% late patency (6 to 20 months, mean 14 months, 30/32 patients). This study suggests the RA can be used safely as an alternative to saphenous vein in coronary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomic study of the collateral blood supply of the sternum

A microdissection study was carried out on ten injected, cleared human sternal specimens. Three types of vessel were identified that have the potential to carry blood to the sternum after mobilization of the internal thoracic artery (ITA): (1) branches of the ITA that supply both the sternum and the pectoralis major ("sternal/perforating branches"), (2) branches of the ITA that supply both the sternum and an adjoining intercostal space ("sternal/intercostal branches"), and (3) posterior intercostal arteries that do not anastomose with an ITA branch but continue past the ITA to reach the sternum. All three types of vessel were found more frequently in the proximal than in the distal half of the sternum. For sternal/perforating and sternal/intercostal vessels to function as collaterals after ITA bypass grafting, their short common trunks of origin must remain intact. The data support the recommendation that the branches of the ITA be ligated as close as possible to the ITA itself to preserve collateral blood flow to the sternum.

A comparison of early mortality and morbidity after single and bilateral internal mammary artery grafting with the free right internal mammary artery

OBJECTIVE

To compare differences in early mortality and morbidity in patients receiving a single internal mammary artery graft (SIMA) with those receiving bilateral internal mammary artery grafts (BIMA) with a free right internal mammary artery (RIMA).

DESIGN

Retrospective analysis of 150 patients undergoing BIMA grafting between 1989-1992 who were carefully matched with 150 patients undergoing SIMA grafting between 1987-1992 for known cardiovascular risk factors, extent of coronary disease, left ventricular function, and number of coronary grafts. Operative variables noted included aortic cross clamp time and bypass time. Postoperative cardiac, respiratory, and wound complications were also noted.

RESULTS

Operative mortality was 2% in the SIMA group and 1.3% in the BIMA group (NS). Other than the prevalence of ventricular arrhythmias (P = 0.025), which were more common in the BIMA group, there were no significant differences between the two groups in terms of postoperative morbidity. At median (interquartile range) follow up of 27.94(0.86) and 23.94(0.74) months for the SIMA and BIMA groups respectively there were no deaths. 87% of the SIMA group and 91% of the BIMA group were free of symptoms at follow up.

CONCLUSIONS

The earlier fears regarding increased early mortality and morbidity after BIMA surgery were not confirmed by this study. All patients receiving both mammary arteries had a free rather than pedicle right internal mammary graft. The early mortality and morbidity reported here compares favourably with previous reports on the use of a pedicle graft.

Cardiac reoperation in patients with bilateral internal thoracic artery grafts

The superior long-term patency of the left internal thoracic artery (ITA) graft is reflected in the enhanced survival of the patients who undergo the procedure, and its use has been shown to lead to a reduced need for reoperation. Evidence is accumulating that use of both ITAs at the primary operation further decreases the need for reoperation, and it is hoped that the use of other arterial conduits will augment this trend. Therefore, the popularity of bilateral ITAs and other arterial conduits in coronary artery operations is growing. However, many surgeons defer using both ITAs at the primary operation partly out of fear of the difficulties that may arise in conjunction with a possible future reoperation. Thirty-six patients underwent reoperation at The Cleveland Clinic Foundation 2 days to 13 years after an earlier bilateral ITA operation because of the progression of native disease, failure of the ITA or vein grafts, or the development of valve disease or end-stage ischemic heart disease. There were four early deaths (11%) and two late deaths, with an average follow-up of 4.3 years (range, 0 to 9.8 years). Forty-seven ITAs were patent preoperatively and 11 crossed the midline. Eleven were patent but stenosed and in need of revision or replacement. Two were damaged during reoperation; both were repaired, but one was ultimately replaced. Although the mortality associated with this procedure is relatively high and these operations are difficult, reoperation can be performed at an acceptable risk, and substantial surgical objectives can be achieved with good long-term results.(ABSTRACT TRUNCATED AT 250 WORDS)

Composite arterial conduits for a wider arterial myocardial revascularization

From October 1991 to May 1993, 130 patients were submitted to myocardial revascularization using complex preformed arterial conduits. The age ranged from 29 to 75 years (mean age, 60.1 years); 121 patients were male. One hundred twenty-six patients had double- or triple-vessel disease. The mean ejection fraction was 0.53 (range, 0.22 to 0.79); only 6 patients had an ejection fraction less than 0.35. In 6 cases the procedure was a reoperation. We used 360 arterial conduits, 163 of which as free grafts (3 left internal mammary arteries, 16 right internal mammary arteries, 86 inferior epigastric arteries, 57 radial arteries, and 1 right gastroepiploic artery). One hundred fifty-four free grafts were anastomosed to one or both internal mammary arteries and one to a radial artery. We constructed 136 complex arterial conduits (branched, lengthened, or both). In 6 cases a double arterial system had to be used in a single patient. There was no operative mortality, and no inotropic or mechanical supports were used. The overall mortality rate was 1.5%. Early angiographic controls (between the 7th and 15th postoperative days) demonstrated 100% patency; late angiographic controls (at a mean interval of 9.5 months after operation) documented a mean patency rate ranging from 94.1% of the radial arteries to 100% of the left internal mammary arteries and right gastroepiploic arteries. At a mean follow-up of 7.2 months (range, 1 to 15 months) all patients are alive without recurrence of symptoms.

Similar hospital morbidity with the use of one or two internal thoracic arteries

The hospital morbidity and mortality of 100 patients operated with two internal thoracic arteries with or without additional vein grafts (BITA group) were compared with a matched group of 100 patients operated with one left internal thoracic artery (ITA) on the anterior descending artery with additional vein grafts (LITA control group). In each study group, 3% of the patients had diabetes mellitus. There was no statistical significant difference in hospital mortality (1% versus 0%), perioperative myocardial infarction (5% versus 1%), low cardiac output (3% versus 5%), rethoracotomy (1% versus 0%), lung complications (13% versus 13%), wound complications (8% versus 8%), other cardiac complications (26% versus 16%), other noncardiac complications (1% versus 4%), median duration of stay in the intensive care unit (1 versus 1 day), and mean duration of stay in the hospital (10.4 versus 10.8 days) between the groups. Logistic regression analysis showed that the number of ITAs used was not a predictor of complications. Thus, there is no difference between the BITA and LITA control group in hospital mortality and morbidity (in patients with a low incidence of diabetes). If an improvement in cardiac event-free and reoperation-free survival is to be expected, the use of both ITAs can be continued in similar patients.

Is the internal thoracic artery the conduit of choice to replace a stenotic vein graft?

Reoperative coronary artery bypass grafting secondary to saphenous vein graft (SVG) stenosis is a mushrooming problem. The internal thoracic artery graft (ITA) provides superior long-term patency, but its flow is limited and may be inadequate to meet large myocardial demands. To evaluate the efficacy of the ITA as a replacement conduit for a stenotic SVG, 387 consecutive patients undergoing reoperative bypass grafting from 1985 to 1990 with a stenotic SVG to a totally obstructed left anterior descending coronary artery (LAD) were analyzed. The patients were divided into four groups according to the management of the previously placed SVG. Group I (n = 155) underwent graft replacement with a new SVG. Group II (n = 90) received an ITA with the old SVG left intact. In group III (n = 37), an ITA was placed to the LAD with an SVG to the diagonal (old graft interrupted). Group IV (n = 104) had an ITA only to the LAD (old graft interrupted). There were 14 deaths (3.6%). Mortality rate was 7.9% for group IV and 2.1% for groups I through III (p = 0.01). Multivariate analyses identified advancing age (p = 0.001), ITA only (p = 0.001), and female sex (p = 0.04) as independent predictors of operative mortality. Evidence of hypoperfusion in the distribution of the LAD was present in 19 patients, all of whom were in group IV (18.9%). Predictors of hypoperfusion were moderate/severe left ventricular function (p = 0.02) and ITA to the LAD with interruption of the old graft (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Sequential internal mammary artery grafts for coronary artery bypass

From 1985 to 1990, 145 patients underwent isolated coronary artery bypass with one (n = 128) or both (n = 17) internal mammary arteries (IMAs) used as sequential bypass grafts. All but 2 patients had angina pectoris preoperatively. A total of 162 sequential IMA grafts were constructed bypassing two (n = 152) or three (n = 10) coronary artery sites as in situ (n = 132) or free (n = 30) grafts. In 12 patients, one IMA was used as a nonsequential graft. Thirty-day mortality was 2.8% (n = 4 patients). Perioperative myocardial infarction occurred in 1 patient (0.7%). Only two sequential IMA grafts failed. Both were used to bypass coronary arteries 1.00 mm in diameter. Mean follow-up was 31 months (range, 6 months to 4.2 years). There were three late deaths. Of 136 survivors followed-up, 121 (89%) were free of angina. Postoperative rotational thallium 201 tomography was done in 73 patients. Myocardial ischemia was detected in 11 diabetic patients (15.1%), but corresponded to a sequential IMA graft in 4 (5.5%) and to nonsequential and venous grafts in 10 patients (13.7%). Coronary revascularization with sequential IMA grafts was safe and effective.