Bilateral Versus Single Internal Mammary Artery Use in Coronary Artery Bypass Grafting: A Propensity Matched Analysis.

BACKGROUND: Bilateral internal mammary artery (BIMA) grafts have demonstrated superior long-term outcomes compared with single internal mammary artery (SIMA) grafts. Despite this, BIMA remains widely underutilised due to perceived technical challenges and concerns regarding wound healing. We sought to examine the morbidity and mortality associated with BIMA use in a propensity-matched cohort of patients. METHODS: From 2009 to 2016, 3,594 consecutive patients underwent coronary artery bypass surgery at three affiliated institutions. Thirty-day (30) mortality and morbidity data were collected prospectively. Propensity-score matched analyses were performed for BIMA versus SIMA use controlling for a number of preoperative characteristics. RESULTS: Overall, 29% of procedures were performed off pump, with a greater proportion in the BIMA group (43% vs. 21%, p<0.001). In the propensity-score analysis consisting of 820 matched pairs, there were similar rates of 30-day mortality (1.3% BIMA vs. 0.9% SIMA, p=0.48) and deep sternal wound infection (1.1% BIMA vs. 0.9% SIMA, p=0.84). The rate of superficial sternal wound infection trended towards being higher in the BIMA group (2.6% vs. 1.3%, p=0.077). The rates of red blood cell transfusions (27.4% vs. 27%, p=0.217), other blood product transfusions (18% vs. 20%, p=0.217), and reoperation for bleeding (2.9% vs. 2.1%, p=0.349) were similar. CONCLUSIONS: Bilateral internal mammary artery use was associated with similar rates of deep sternal wound infection compared to SIMA use, with a preponderance of superficial sternal wound infections that did not result in increased mortality or transfusion requirements. The use of BIMA should be more widely considered for coronary artery bypass surgery.

Impact of Discontinuation of Antiplatelet Therapy Prior to Isolated Valve and Combined Coronary Artery Bypass Graft and Valve Procedures on Short and Intermediate Term Outcomes.

BACKGROUND: A change in cardiac surgery practice over the past decade has seen an increase in urgent or inpatient referrals for surgery, with antiplatelet therapy often continued up until surgery. This study aims to identify the optimal timing for administration of aspirin to minimise risk of perioperative morbidity and mortality. METHODS: From a prospectively compiled database collected by the Australian and New Zealand Society of Cardiac and Thoracic Surgeons, we identified 8294 patients undertaking combined CABG and valve or isolated valve procedures while discontinuing aspirin. Time points for cessation of antiplatelet therapy were categorised as follows: <2 days, 3-7 days or >7 days preoperatively. We evaluated the association of adverse in-hospital events and intermediate term survival in each time category. RESULTS: Discontinuing aspirin 3 to 7 days from surgery decreased rates of perioperative MI (HR=0.300, p=0.027), return to theatre (HR=0.560, p=0.002) reduced drain output (HR=0.757, p=0.000) and red blood cell and platelet transfusions (HR=0.719, p=0.000 and HR=0.604, p=0.000 respectively) compared to patients continuing aspirin until <2 days from the procedure. Stopping aspirin <2 days from the date of surgery increased risk of perioperative MI (HR=5.919, p=0.000), reoperation for bleeding (HR=2.076, p=0.001), returning to theatre (HR=1.781, p=0.000), ICC drain losses (HR=1.337, p=0.000) and transfusion demands for red blood cells (HR=1.381, p=0.000) and platelets (HR=1.450, p=0.000) when compared to those discontinuing aspirin >7 days from surgery. CONCLUSION: Late discontinuation of aspirin before combined coronary artery bypass graft and valve procedures results in greater rates of bleeding and transfusion requirements. Earlier discontinuation of aspirin results in no benefit in intermediate term survival.

Lipid management in high risk coronary patients: how effective are we at secondary intervention?

OBJECTIVE: To assess the proportion of patients who achieve and maintain target lipid levels during optimum long term follow up after coronary bypass surgery. METHODS: From a prospectively compiled database, we identified 440 patients followed for up to 13 years after CABG as part of a radial artery randomised controlled trial. All available lipid assays conducted during the follow-up period were collected from pathology databases. These were used to calculate the annualised mean lipid exposure for each patient. Based upon National Heart Foundation guidelines, we determined the proportion of patients whose mean lipid exposure attained target levels (total cholesterol <4.0 mmol/L, LDL-C <2.0 mmol/L, HDL-C >1.0 mmol/L and triglycerides <1.5 mmol/L). This was compared with the proportion who had achieved these targets pre-operatively and on their most recent cholesterol measurement. RESULTS: 6077 lipid studies (total cholesterol, LDL, HDL and triglycerides) in total were obtained. In those who had baseline data available, target levels for total cholesterol, HDL-C, LDL-C and triglycerides were attained pre-operatively by 16%, 64%, 14% and 39% of patients respectively. Annualised mean lipid exposures during up to 13 years of follow up for all patients revealed somewhat improved but still suboptimal target attainment figures of 24%, 83%, 20% and 53%. The most recent review shows the greatest improvement at 47%, 68%, 43% and 62% respectively. Of 141 diabetic patients, target attainment was significantly higher for total cholesterol (31%; p=0.038) and LDL-C (28%; p=0.006) but lower for HDL-C (75%; p=0.002) and triglycerides (40%; p<0.001). CONCLUSION: Despite some improvements seen over careful follow up, only HDL-C targets appear attainable for the majority of CABG patients. Over half still do not achieve non-HDL national lipid targets.

Nausea, vomiting and return of bowel function after colorectal surgery.

BACKGROUND: Although patterns of return of bowel function (ROBF) following colorectal surgery with enhanced recovery after surgery (ERAS) programmes have been well delineated, regular morphine use is uncommon. This study describes the patterns of post-operative nausea and vomiting (PONV) and ROBF in this context. METHOD: Patients undergoing elective major colorectal surgery on an ERAS programme over 1 year were included. Patient details, intra-operative course, post-operative management, outcomes and complications were collected retrospectively from clinical records. Statistical analysis was performed using Stata version 12. RESULTS: A total of 136/142 (96%) patients received morphine for post-operative analgesia. Most (112/142, 79%) experienced either no vomiting (87/142, 61%) or small amounts (25/142, 18%). On average, patients without an ileostomy passed flatus and opened their bowels after 2.4 and 4.3 days, those with an ileostomy taking 1.5 and 2.1 days. Vomiting was not related to ROBF (P = 0.370) or overall complications; wound complications (odds ratio (OR) = 8.1, 95% confidence interval (CI): 2.0-32.5), electrolyte abnormalities (OR = 2.9, 95% CI: 1.2-7.1) and length of stay (hazard ratio = 1.3, 95% CI: 1.2-1.5) were related. CONCLUSION: Most patients do not experience PONV in this context. ROBF is predictable without prolonged delays. This information could be used to allow confident early discharge and identify patients whose deviation from normal may indicate complications.

Regression of coronary disease after bypass surgery: Urban myth or common finding?

OBJECTIVES: Coronary artery disease has been viewed as a relentless, progressive disease. We sought to describe the prevalence and distribution of regression of native vessel disease in coronary artery bypass patients and characterize its relationship with bypass grafting. METHODS: Among 619 patients who underwent bypass surgery in a radial artery trial, 405 had follow-up angiography available a mean of 6.2 ± 3.1 years (range, 0-14) after surgery. The percentage of diameter stenosis of each major native coronary vessel was reported by 3 cardiac specialists and classified into grades of nonflow limiting (0%-39%), moderate (40%-69%), flow limiting (70%-80%), severely stenosed (81%-99%), and occluded (100%). Native vessel disease regression was defined as decrease in 1 or more grades of stenosis between the pre- and postoperative angiograms. RESULTS: A total of 1742 native coronary arteries had preoperative stenosis of at least 40% and were included in the present analysis, receiving 753 arterial grafts and 391 saphenous vein grafts. Overall, the prevalence of disease regression was 19.7%, and 45% of patients demonstrated regression in 1 or more vessels. The presence of an arterial graft increased the likelihood of disease regression (21.3% compared with 16% for venous bypassed vessels, P = .012) as did the location in the left circulation (22.6% compared with 13.9% for the right circulation, P < .001) and having a flow-limiting (≥70%) lesion (21.9% compared with 9.8% for moderate lesions, P < .001). CONCLUSIONS: Native coronary artery disease regression after coronary artery bypass grafting is common and affected by conduit type, vessel location, and lesion severity. Surgeons must consider these factors when assessing the requirement for bypass grafts in a borderline lesion.

Effect of lipid exposure on graft patency and clinical outcomes: arteries and veins are different.

OBJECTIVES: We evaluated the influence of lipid exposure upon conduit patency in long-term follow-up after primary CABG. METHODS: From a prospectively compiled database, we identified 1207 grafts (436 SV and 771 mixed arterial grafts) among 413 CABG patients with 9.4 ± 2.4 years of follow-up (range 3-13). Surveillance angiography was performed as part of a randomized trial. All available lipid assays were collected from pathology laboratories, and from these, mean annualized lipid exposure was calculated for total cholesterol, HDL, LDL and triglycerides. Angiographical and clinical data were analysed against lipid exposure. Graft failure was defined as occlusion, string sign or >80% stenosis. RESULTS: Six thousand and seventy-seven lipid measurements were obtained, and there were 154 failed grafts. Three hundred and eleven patients received at least one vein graft, and all 413 patients received at least one arterial graft. Overall, only HDL levels were inversely correlated with graft failure, with total cholesterol and LDL showing no associations in a mixed pool of arterial and venous grafts. To assess whether total/LDL cholesterol had no effect or were exerting competing effects in arteries and veins, separate multivariate analyses were performed. Venous graft failure was associated with increased total cholesterol/HDL (P=0.006) and LDL/HDL (P=0.032). By contrast, elevated total cholesterol was correlated with a reduced risk of arterial graft failure (OR for graft failure 0.705, P 0.023) with increasing LDL cholesterol following a similar trend (OR for graft failure 0.729, P=0.051). CONCLUSION: Sub-fractions of dyslipidaemia known to be risk factors for native vessel disease appear to similarly influence vein grafts. Arterial conduits are at least more resistant to the effects of high lipid exposure, and appear to be protective. These results favour the use of arterial grafts in patients with poorly controlled dyslipidaemia.

Should all moderate coronary lesions be grafted during primary coronary bypass surgery? An analysis of progression of native vessel disease during a randomized trial of conduits.

OBJECTIVE: Whether to graft a moderately stenosed coronary vessel remains debatable. We investigated whether grafting such vessels is warranted based on angiographic evidence of disease progression. METHODS: Of 619 patients who underwent on-pump coronary artery bypass grafting in an ongoing, randomized radial artery trial, 405 have at least 1 follow-up angiogram at a mean of 6.2 ± 3.1 years (range, 0-14 years) after surgery. Percent diameter stenosis in each major native vessel was reported by 3 cardiac specialists and classified as either moderate (40%-69%) or severe (≥70%) stenosis. Progression of native vessel disease and graft patency were determined by comparison of pre- and postoperative angiography. RESULTS: A total of 3816 native vessels and 1242 bypass grafts were analyzed, of which 386 moderate preoperative lesions were identified, 323 of which were grafted. In all territories, grafted vessels had greater risk of disease progression than ungrafted equivalents (43.4% vs 10.5%, P < .001). Moderate lesions were more likely than severe lesions to remain unchanged on follow-up angiography (52.6% vs 31.1%, P < .001). Only 1 in 7 moderate lesions in the right coronary artery exhibited significant progression during follow-up if left ungrafted, whereas the likelihood of progression in left-sided counterparts approached 50%. Arterial and vein grafts to left-sided moderately stenosed vessels had excellent patency (83% and 77% at 8 years, respectively), which was not matched by right-sided grafts (P = .051). Placement of a graft for a moderate lesion was associated with significantly greater incidence of disease progression, most marked in the right coronary territory. CONCLUSIONS: The greater risk of progression of left-sided moderate lesions, and high graft patency rates when bypassed, suggests that the balance of clinical judgment lies in favor of grafting moderate left-sided lesions. In the right coronary system, however, a lesion is likely to remain moderate if left ungrafted and, with a low risk of progression, it may be reasonable to leave these vessels undisturbed.

Long-term impact of radial artery harvest on forearm function and symptoms: a comparison with leg vein.

OBJECTIVE: The radial artery (RA) has gained popularity as a conduit for coronary artery bypass surgery despite a paucity of patient-centered analysis of long-term quality of life after its removal. We sought to characterize forearm function and symptoms after RA harvest and compare these with those associated with saphenous vein (SV) removal. METHODS: A total of 408 patients from an RA trial completed a questionnaire up to 14 years after primary coronary artery bypass surgery. The survey included 7 statements concerning hand and forearm symptoms or limitations in daily life and 4 questions on concerns associated with arm or leg scars. A total of 230 patients had received an RA graft (RA group). Responses were graded in order of severity from 0 to 7, with greater than 3 (mild concern) being regarded as a significant symptom. Mean response to each question and total scores were compared with the non-RA harvest group. Comparisons were also made with responses to the same questionnaire completed preoperatively and 3 months postoperatively. In patients who had both RA and SV removal, we compared the impact of a forearm scar on quality of life with that of a leg scar. RESULTS: The mean duration of follow-up was 9.3 years (range, 4-14 years), and the response rate was 83%. In the RA group, 92% to 99% reported no significant symptoms, with the most frequent concerns relating to pain and numbness (8% each), but this was not significantly higher than in those who had not had an RA harvested. In the RA group, the mean scores for scar appearance and discomfort were 0.95 and 0.93, respectively (where 1 = no concern), suggesting satisfactory cosmesis and no impact on function. Symptom severity was significantly worse in 6 of 7 questions when compared with preoperative responses and in 4 of 7 items compared with 3-month follow-up, indicating a general deterioration in function over long-term follow-up. In those who had both the RA and SV harvested, patients reported more scar discomfort associated with SV harvest at 3 months (1.69 vs 1.34, P < .001) and in the present questionnaire (1.21 vs 0.97, P = .002). Concerns with scar appearance were no different between the arm and leg. CONCLUSIONS: RA harvesting is associated with high patient satisfaction and less scar discomfort than SV removal. Overall, functionality declines with time, and a small proportion of patients seem to experience forearm pain and numbness. However, this is not different than in those without artery removal and may therefore be unrelated to the effects of surgery.