Clinical outcomes in patients undergoing coronary artery bypass grafting with preferred use of the radial artery

Risk factors for decreased cardiac output after coronary artery bypass grafting: a prospective cohort study

BACKGROUND

No previous study has investigated the predictive risk factors of the nursing diagnosis of risk for decreased cardiac output after coronary artery bypass grafting (CABG).

AIMS

This study aimed to identify the predictive risk factors of the nursing diagnosis of risk for decreased cardiac output after CABG.

METHODS

This was a prospective cohort study performed at a cardiac university hospital in São Paulo, Brazil and 257 adult patients undergoing CABG were included. Potential risk factors for low cardiac output in the immediate post-operative period were investigated using the patients' medical records. Univariate analysis and logistic regression were used to identify the predictive risk factors of decreased cardiac output. The area under the receiver operating characteristic curve was calculated as a measure of accuracy. The variables that could not be analysed through logistic regression were analysed through Fisher's exact test.

RESULTS

One hundred and ninety-five patients had low cardiac output in the immediate post-operative period. The predictive risk factors included age ⩾60 years, decreased left ventricle ejection fraction, not using the radial artery graft, positive fluid balance and post-operative arrhythmia that differed from the pre-operative arrhythmia. This model predicted the outcome with a sensitivity of 62.9%, a specificity of 87.2% and an accuracy of 81.5%. The variables analysed through Fisher's exact test included heart failure, re-exploration and bleeding-related re-exploration.

CONCLUSIONS

The predictive risk factors for the nursing diagnosis of risk for decreased cardiac output after CABG were found. These results can be used to direct nurses in patient monitoring, staff training and nursing team staffing.

Effects of intraoperative diltiazem infusion on flow changes in arterial and venous grafts in coronary artery bypass graft surgery

Objective

This study aimed to show the effects of intra-operative diltiazem infusion on flow in arterial and venous grafts in coronary artery bypass graft surgery.

Methods

Hundred fourty patients with a total of 361 grafts [205 (57%) arterial and 156 (43%) venous] underwent isolated coronary surgery. All the grafts were measured by intraoperative transit time flow meter intra-operatively. Group A (n=70) consisted of patients who received diltiazem infusion (dose of 2.5 microgram/kg/min), and Group B (n=70) didn't receive diltiazem infusion.

Results

Mean graft flow values of left internal mammary artery were 53 ml/min in Group A and 40 ml/min in Group B (P<0.001). Pulsatility index (PI) values of left internal mammary artery for Group A and Group B were 2.6 and 3.0 respectively (P<0.001). No statistically significant difference was found between venous graft parameters.

Conclusion

We recommend an effect of diltiazem infusion in increasing graft flows in coronary artery bypass graft operations.

Radial artery as graft for coronary artery bypass surgery: Advantages and disadvantages for its usage focused on structural and biological characteristics

Radial artery (RA) is the most popular arterial graft after the left internal thoracic artery in both low- and high-risk patients undergoing coronary artery bypass grafting. Various arterial grafts such as the right internal thoracic artery, the right gastroepiploic artery, and the inferior epigastric artery have also gained ground over the past 30 years because of the intimal hyperplasia and atherosclerosis of the saphenous vein leading to late graft occlusion. In this review article we would like to present the utility of the RA as a graft, focused mainly on its structural and biological characteristics.

Predischarge angiographical evaluation of radial artery graft harvested by endoscopic harvesting system

OBJECTIVE

Endoscopic radial artery harvesting (ERAH) has superior cosmetic advantages over conventional harvesting methods. With instrumental advancements, these techniques have become easier to adopt and require less time to learn. In most reported cases, the quality of harvested conduits is discussed based on macroscopic and histologic examinations and clinical outcomes. However, predischarge angiography gives a straightforward answer regarding quality of harvested conduit. The aim of this study is to assess the quality of endoscopically harvested radial artery by predischarge angiographic evaluation.

METHODS

Endoscopic procedure using VasoView 4 system was performed in 87 patients between September 2004 and December 2007, and 78 predischarge angiographical evaluations were completed and reviewed. Mean age of the patients was 66 ± 10 years and 18% were women. After ERAH was performed, accompanying veins were dissected by ultrasound scalpel. All conduits were as aortocoronary bypass under cardiopulmonary bypass.

RESULTS

Mean arm ischemic time was 32 ± 13 minutes and length of harvested conduit was 17.8 ± 1.3 cm. Predischarge angiography demonstrated two occlusions at the proximal anastomosis in the 51st and 71st cases, although intraoperative flow study showed normal flow patterns in both cases. Stenosis in the conduits was observed in the first, sixth, and seventh cases. No further angiographical problems were found in the remaining conduits.

CONCLUSIONS

Based on the angiographical results, problems with the harvested conduits occurred only in initial period. ERAH with VasoView system provides satisfactory angiographical quality after initial learning curve.

Harvesting radial artery and neurologic complications

BACKGROUND

Determination of the incidence, mechanisms, and diagnosis of hand complications after radial artery (RA) harvesting in coronary surgery (CABG).

METHODS

The study group (RA group) includes 54 patients who underwent RA harvesting in CABG operation. The control group (noRA group) consists of 131 patients who underwent CABG without the use of RA graft. The average follow-up time was 16.36 +/- 5.13 months. The patients were examined clinically, (a) for motor function abnormalities associated with radial and median nerve damage and (b) for sensory abnormalities, and the function of radial nerve was determined by eliciting the brachioradialis reflex. They answered in a formal scripted questionnaire to elicit symptoms and clinical points attributable to nerve damage during RA harvest, such as hand weakness, thumb weakness, sensation abnormalities on the back and on the palm side of the forearm, hand numbness, hand-reversible paresis or forearm infection postoperatively, and any other upper limb abnormality.

RESULTS

Of the patients in the RA group, 34.09% reported left-hand abnormality after operation. On the other hand, in the noRA group left-hand abnormality was reported in 18.68% of patients. In the RA group sensation abnormality was reported in 34.09% of patients and thumb weakness alone was reported in 6.82% of patients. There was a statistically significant difference between the two groups. Low EuroSCORE was the predicting factor for motor abnormalities.

CONCLUSIONS

More knowledge has been added about the neurologic complications after RA harvesting lately. We demonstrated the rate of motor and sensory abnormality, the potential mechanisms of these complications caused by surgical trauma or devascularization, and any predictive factors of complications. Optimal surgical techniques to avoid the damage of the responsible nerves are recommended.

A Safe and Cost-Effective Approach to Minimally Invasive Radial Artery Harvesting

PURPOSE

We describe a minimally invasive, cost effective, and safe method of radial artery harvesting.

DESCRIPTION

After obtaining informed consent and completing a preoperative evaluation, 169 radial arteries were harvested. Harvesting was accomplished through a 3-cm proximal mid forearm incision with exposure provided by a modified self-retaining lighted retractor.

EVALUATION

A total of 169 radial arteries were successfully harvested. The average incision length was 2.9 cm, radial artery length was 15.8 cm, and harvest time was 32.7 minutes. No trauma to the artery or graft spasm was evident. No procedure required conversion to an open technique. Superficial cellulitis occurred in 2 patients (1.2%) and wound infection in 1 (0.6%). Three patients (1.8%) experienced intermittent residual dysesthesia. All of the patients were highly satisfied with the excellent aesthetic results. This approach allowed for a substantial cost savings compared with other minimally invasive techniques.

CONCLUSIONS

Direct minimally invasive radial artery harvesting is an acceptable alternative approach to radial artery harvesting. This method is safe, cost effective, easily reproducible, and aesthetically pleasing.

Role of Radial Artery Graft in Coronary Artery Bypass Grafting

The use of the radial artery (RA) as a coronary artery bypass graft has assumed a revival and thus a multitude of issues have arisen surrounding the routine and widespread use of this conduit in myocardial revascularization. There has been no uniformity regarding harvest techniques, assessment of the adequacy of hand collateral circulation, antispasm protocols, selection of target vessels, and the site of proximal anastomosis. It is widely believed and practiced that the RA should be harvested as a pedicle graft and preferably be used to bypass critically stenosed (>70% stenosis) coronary arteries. It is used either as a free graft with proximal anastomosis to the ascending aorta or as a composite arterial graft along with the left or right internal thoracic artery. The patency of RA grafts depends on the severity of the target coronary artery stenosis and target artery location rather than its use as an aortocoronary conduit or composite graft. In this article, we reviewed the current knowledge regarding the use of RA grafts as a coronary bypass conduit in an attempt to suggest a few acceptable strategies concerning the above issues in a given clinical scenario.

Effects of hydrostatic distention on in vitro vasoreactivity of radial artery conduits

BACKGROUND

Surgical preparation of coronary conduits may affect early and long-term patency through endothelial and smooth muscle injury. We investigated the effect of hydrostatic distention on the in vitro endothelial function and contractile properties of the human radial artery.

METHODS

Human radial arteries were harvested and distended to physiologic pressure or suprasystemic pressure (>300 mm Hg) by using heparinized whole blood for 2 minutes. Distal segments were retrieved and prepared into 3-mm rings. These were mounted and stretched to optimum resting tension in oxygenated Krebs solution at 37 degrees C. Contraction responses to potassium, norepinephrine, and serotonin and relaxation responses to acetylcholine and nitroprusside were evaluated. Undistended radial artery segments were used as controls.

RESULTS

Vasocontraction to all 3 contractile agonists was significantly different between groups. The radial artery subjected to suprasystemic pressure distention achieved the lowest percentage of maximum contraction (potassium, P <.001; norepinephrine, P <.05; serotonin, P <.05). The median effective concentration was also significantly reduced in this group, indicating increased sensitivity to all 3 agonists. Receptor-mediated contractility was significantly reduced in both distended groups when compared with controls. Relaxation to acetylcholine and nitroprusside was significantly reduced in the suprasystemic pressure-distended group, which had a tendency to vasospasm when exposed to a physiologic concentration of acetylcholine (10(-6) mol/L). Median effective concentrations for both acetylcholine and nitroprusside were not different between groups.

CONCLUSIONS

Excessive distention of the radial artery leads to a significant reduction in vasoreactivity, which may be attributed to a disruption of the vascular endothelium and media, with a propensity for graft spasm with exposure to acetylcholine.

Endoscopic Radial Artery Harvest for Coronary Artery Bypass Grafting: Initial Clinical Experience

BACKGROUND

Recently, an endoscopic technique was developed to harvest the radial artery (RA) via a 3-cm wrist incision in patients undergoing coronary artery bypass graft (CABG). The aim of this study was to evaluate our initial clinical experience with this technology.

METHODS

Data were prospectively collected on 75 consecutive patients undergoing CABG with endoscopic RA harvest using the Ultra-Retractor (CardioVations, Somerville, NJ, USA) and the harmonic scalpel (Ethicon Endo-Surgery, Cincinnati, OH, USA).

RESULTS

There were 66 men (88%) and 9 women (12%) with a mean age of 60 years (range, 31-77 years). Forty-eight (64%) of cases had non-elective surgery. Thirty-one (41%) of patients had diabetes. Sixty seven percent of the operations were performed on pump and 33% off pump. Average RA harvest time was 66 minutes (range, 25-120 minutes) with a significant learning curve (75 minutes for the first 20 cases and 63 minutes for the last 50 cases). Two (2.6 %) radial arteries were discarded, one because of extensive calcifications and the other because of damage to the conduit. No patients suffered death, perioperative myocardial infarction, or stroke. There was one reexploration of the forearm for a tunnel hematoma. Follow-up was achieved in 100% of patients and averaged 3.6 months (range, 0.5-13 months). Two patients died during the follow-up. There were no myocardial infarctions or reinterventions, with 96% of patients in functional class I /II. There were no motor deficits. There were no sensory deficits in the distribution of the lateral antebrachial cutaneous nerve, but transient mild dorsal thenar numbness or paresthesias were observed in 86% of patients. Cosmetic results were defined as good to excellent in 82% of patients.

CONCLUSIONS

Short-term results of endoscopic RA harvest are excellent. There is a significant learning curve. Longterm follow-up as well as structural and functional assessments of the conduit are indicated.

Complications after radial artery harvesting for coronary artery bypass grafting: our experience

BACKGROUND

The aim of this study was to evaluate the incidence of complications in the upper limbs as a new event after radial artery (RA) harvesting for coronary artery bypass grafting (CABG).

METHODS

From June 1997 to August 2001, the RA graft was used in 271 patients who underwent cardiac surgery at our department. These patients were prospectively reviewed. All patients were preoperatively examined to determine the presence of normal sensation and circulation in the upper limbs; then we evaluated the incidence of complications at discharge, 8 weeks, and 6 months.

RESULTS

No donor arms developed symptoms of ischemia or motor dysfunction. At 8 weeks 2 patients (0.7%) reported donor arm weakness, and cutaneous paresthesia was noted postoperatively in 10 upper limbs (3.7%). The univariate statistical analysis showed that significant risk factors for persistent cutaneous paresthesia were diabetes and smoking.

CONCLUSIONS

This study demonstrates that complications after harvesting the RA for CABG are a rare consequence. The main symptom is a persistent cutaneous paresthesia present in 10 patients at 6-month follow-up.

Radial artery harvesting for coronary bypass operations: neurologic complications and their potential mechanisms

OBJECTIVES

We sought to determine the incidence of self-reported neurologic hand complications after radial artery harvest for coronary artery bypass grafting.

METHODS

Between February 20, 1996, and December 31, 1999, 615 patients underwent coronary bypass operations with radial arteries. A scripted telephone interview was performed, collecting data on perceived thumb weakness and sensation abnormalities in the distribution of the radial nerve in 560 patients. The average time to follow-up interview was 14.5 +/- 9 months.

RESULTS

Neurologic complications were reported in 30.1%, decreased thumb strength in 5.5%, and any sensation abnormality in 18.1% of patients. There was a high rate of symptom improvement over an average of 8.7 +/- 7.5 months, such that only 12.1% of patients reported symptoms without any improvement. Associations between thumb weakness and sensory abnormalities imply median nerve damage in some patients. There were statistically significant associations between neurologic complications and diabetes, peripheral vascular disease, elevated creatinine levels, smoking, and number and site of radial artery harvest.

CONCLUSIONS

The overall rate of self-reported neurologic complications after radial artery harvest was higher than previously reported. These symptoms may be attributable to radial and median nerve injury caused by trauma and devascularization. These data have important implications not only in attempting to improve harvesting techniques but also in guiding informed consent before coronary artery bypass grafting.

Comparison of deposits of versican, biglycan and decorin in saphenous vein and internal thoracic, radial and coronary arteries: correlation to patency

BACKGROUND

Matrix proteoglycans versican, biglycan and decorin are important determinants of vessel-wall structure and pathology. Thickened myxoid intimas typical of restenosis and early atherosclerosis are enriched in versican and biglycan, proteoglycans that promote proliferation and migration of smooth muscle cells and bind lipoproteins. In contrast, compact fibrous intimas are characterized by decorin.

OBJECTIVE

To compare the distribution patterns of these matrix proteoglycans, and changes induced by organ culture in coronary artery, saphenous vein, internal thoracic artery (ITA), and radial artery, and correlate differences to patency.

METHODS

Vessels were collected at the time of bypass surgery and heart transplantation and either fixed for immunohistochemistry or prepared for organ culture. Vessels in culture were labelled with [3H]-glucosamine and processed for autoradiography and immunohistochemistry. Distribution patterns for proteoglycans and radio-labelling were determined morphometrically.

RESULTS

Distribution profiles in coronary artery and saphenous vein were similar, with relatively high levels of subendothelial versican and biglycan and low levels of decorin. In culture subendothelial incorporation of [3H]-glucosamine and immunostaining for versican and biglycan, but not decorin, were significantly increased. In contrast, the thin intima of the ITA was relatively enriched in decorin compared with the medial layers and in culture intimal staining for decorin increased markedly compared with a modest increase for biglycan and no change for versican. There was an even distribution in radial artery of all three proteoglycans across the intima without subendothelial accumulations. In culture there was an increase in staining intensity for proteoglycans of the radial artery. Neither the ITA nor radial artery exhibited an increase in subendothelial incorporation of [3H]-glucosamine in culture.

CONCLUSIONS

The distributions of proteoglycans, and responses to culture correlate to the known differences in patency between grafted saphenous vein and ITA and predict that the radial artery will outperform the saphenous vein but might not be as good as the ITA for long-term patency.

Nitroglycerin is preferable to diltiazem for prevention of coronary bypass conduit spasm

BACKGROUND

Diltiazem is widely used to prevent radial artery spasm after coronary bypass grafting (CABG). However, recent in vitro and in vivo studies have shown that nitroglycerin is a superior conduit vasodilator compared to diltiazem. A clinical comparison of these agents in patients undergoing CABG has not been previously performed.

METHODS

One hundred sixty-one consecutive patients undergoing isolated CABG with the radial artery were prospectively randomized to 24-hour intravenous infusion of nitroglycerin or diltiazem followed by 6-month treatment with a daily dose of isosorbide mononitrate (n = 84) or diltiazem CD (n = 77). Analyses were performed on "intention-to-treat" basis.

RESULTS

Crossovers because of low cardiac output, complete heart block, or sinus bradycardia occurred in 5 patients in the diltiazem group and none in the nitroglycerin group (p = 0.05). Operative mortality (nitroglycerin, 1.2% versus diltiazem, 1.3%), major morbidity (14% versus 16%), perioperative myocardial infarction (1.2% versus 0%), peak serum creatinine phosphokinase MB fraction levels (27 versus 21 U), intensive care unit stay (34+/-19 versus 38+/-30 hours) and total hospital length of stay (4.7+/-1.4 versus 4.7+/-1.3 days) were similar (p = not significant for all). Cardiac pacing was required more often in the diltiazem group (28% versus 13%, p = 0.01). Follow-up longer than 2 months was available in 145 patients (90%). Follow-up mortality (nitroglycerin, 1.2%; diltiazem, 1.3%), myocardial infarction (6%, versus 5%), and reintervention (8% versus 6%) rates and average angina class (1.3+/-0.7 versus 1.1+/-0.4) were similar (p = not significant for all). Thallium stress test obtained in 117 patients showed abnormal perfusion in the radial artery territory in only 4 patients (3%), 2 in each group (p = not significant). Treatment with diltiazem was more costly ($16,340 versus $1,096).

CONCLUSIONS

Nitroglycerin is preferable to diltiazem for prevention of conduit spasm. Nitroglycerin is safe, effective, better tolerated, and less costly than diltiazem, and therefore, should be the agent of choice.

The radial artery: which place in coronary operation?

Previous long-term studies have shown unsatisfactory patency of saphenous vein grafts, compared with internal mammary artery grafts. Recently, the use of the radial artery as a coronary artery bypass graft has enjoyed a revival, on the basis of the belief that it will help improving long-term results of coronary operations. The recent report of encouraging 5-year patency rates, supports its continued use as a bypass graft. In this paper, we review the current knowledge about the radial artery as a bypass graft, with special emphasis on the clinical results.

Risk factors for radial artery harvest site infection following coronary artery bypass graft surgery

Radial arteries increasingly are used during coronary artery bypass graft (CABG) surgery. Although risk factors for saphenous vein harvest site infection (HSI) have been reported, rates of and risk factors for radial artery HSI are not well established. We compared rates of radial artery HSI that were detected by 2 surveillance methods, regular and heightened. Risk factors were determined by a case-control study. We identified 35 radial artery HSIs ("case sites") in 26 case patients. The radial artery HSI rate was significantly higher during heightened surveillance than during routine surveillance (12.3% vs. 3.1%, respectively; P=.002). Multivariate analysis showed that diabetes mellitus with a preoperative glucose level >/=200 mg/dL (odds ratio [OR], 4.4; P=. 01) and duration of surgery >/=5 h (OR, 3.1; P=.02) were independent risk factors for radial artery HSI. Infection is a common complication of radial artery harvesting for CABG surgery, and infection rates are dependent on the intensity of surveillance. We identified preoperative hyperglycemia and surgery duration as independent risk factors for radial artery HSI.

Nitroglycerin is superior to diltiazem as a coronary bypass conduit vasodilator

BACKGROUND

Recent reports of improved radial artery patency have been attributed, in part, to routine use of diltiazem to prevent vasospasm. However, diltiazem is costly, and its use may be associated with negative inotropic and chronotropic side effects. This study compares the vasodilatory properties of diltiazem to those of nitroglycerin.

METHODS

In vitro, with the use of organ chambers, the vasodilatory properties of diltiazem and nitroglycerin were compared in matched segments of radial artery, internal thoracic artery, and saphenous vein that were harvested from the same patients (n = 11). The vasodilatory response of the radial artery to intravenous diltiazem or nitroglycerin was compared in vivo (n = 10) with the use of ultrasonographic measurements of radial artery diameter.

RESULTS

The maximum relaxation of radial artery (100% +/- 4%), internal thoracic artery (96% +/- 4%), and saphenous vein (100% +/- 3%) to nitroglycerin were significantly greater than the response to diltiazem (33% +/- 6%, 22% +/- 7%, and 34% +/- 5%, respectively; P <.001). The thromboxane mimetic, U46619, induced radial artery spasm with a median effective concentration of 3.7 +/- 0.8 nmol/L. Physiologic concentrations of nitroglycerin (0.1+/- micromol/L) significantly inhibited the radial artery response to U46619 (median effective concentration, 6.2 +/- 1.1 nmol/L; P =.046), whereas diltiazem (1 micromol/L) did not (median effective concentration, 3.7 +/- 0.8 nmol/L; P =.64). In vivo, nitroglycerin increased radial artery diameter 22% +/- 3%, which was significantly greater than diltiazem (3% +/- 0.5%; P =.001).

CONCLUSION

Nitroglycerin is a superior conduit vasodilator and is more effective in preventing graft spasm than diltiazem. Nitroglycerin should be strongly considered as the drug of choice to prevent conduit spasm after coronary bypass grafting.

Coronary artery surgery: the end of the beginning

In each of the first three decades of myocardial revascularization, conventional treatment has been revised completely. This lecture comments on three areas of discovery that have shaped the evolution of myocardial revascularization: science, technology development, and revascularization. The discoveries in all three areas are inexorably interrelated. The single greatest lesson learned so far is that conduit performance carries more prognostic weight than any other factor. We have observed that vein graft atherosclerosis is predictable, and that the first-generation lipid lowering drugs have a favorable effect in patients who achieve marked LDL reduction. Biologically better revascularization begins with use of the internal thoracic artery for grafting to the anterior descending coronary artery. As the results of internal thoracic artery grafting are widely reported, arterial bypass revascularization has expanded, notably by radial and gastroepiploic arteries. The results of bilateral internal thoracic artery grafting are discussed, including large-scale registry results of internal thoracic artery usage in the United States. The internal thoracic artery is significantly underutilized. Diabetes affects both endoluminal and surgical revascularization. The new pharmacology in cardiology interventions shows promise in diminishing restenosis and thrombosis even in diabetic patients. Conversely, extended internal thoracic artery grafting may also benefit diabetic patients. Now we are entering a new age of minimally invasive coronary surgery. We have passed through the early stages of mini-thoracotomy, and we are moving on to access through 1-cm ports, intrathoracic cannulation, antegrade and retrograde myocardial protection, and computer guided three-dimensional vision and instrumentation. The potential for robotic control adds greater precision, ease of use, and safety. This new technology will be integrated with diagnostic information, intraoperative monitoring, anesthesia and perfusion data, cost accounting, and surgical note transcription. The operating room of the future will package intraoperative information and is adaptable to all surgical specialties. The future of coronary artery surgery will depend on minimally invasive techniques, all-arterial grafting, and selective lipid modification to reduce progressive atherosclerosis. The conclusion of this decade marks the end of the beginning. The new generation of cardiothoracic surgeons will share in an array of technology and research unmatched in previous decades.