Use of extrafascially harvested radial artery for coronary artery revascularization: technical considerations

Endoscopic radial artery harvesting procedure for coronary artery bypass grafting

Development and adoption of endoscopic minimally invasive saphenous vein harvesting prompted its application to the radial artery in an effort to minimize surgical trauma. Recently, we reported that endoscopic radial artery harvesting was associated with better wound appearance and it proved to be safe and effective, with less pain and fewer wound complications than the open surgical technique. Based on this positive experience, our institution adopted endoscopic radial artery harvesting, hence the aim of this manuscript is to describe the minimally invasive endoscopic radial artery harvesting for coronary artery bypass grafting.

Endoscopic versus open radial artery harvesting for coronary artery bypass grafting

BACKGROUND AND AIM OF THE STUDY

The radial artery has become the artery of choice after both internal thoracic arteries for coronary artery bypass grafting (CABG). This study compares wound healing and arm complications after endoscopic versus open radial artery harvesting.

METHODS

From January 2002 to July 2004, 509 patients underwent CABG including a radial artery conduit. Thirty-nine had endoscopic and 470 conventional open radial artery harvesting. A propensity score was used to obtain 1:3 matching of all endoscopic to 117 open-harvesting patients. Postoperative wound healing, local neurologic deficits, wound infection, and pain scores were compared.

RESULTS

Wound healing: 34 of 39 endoscopic wounds exhibited a perfect Hollander score versus 339 of 470 open-harvest wounds (p = 0.01). Wound appearance was better for endoscopic harvesting (p = 0.004). Three incomplete neurologic deficits were observed after open harvesting versus one complete neurologic deficit after endoscopic harvesting that recovered prior to hospital discharge. Incidence of wound infection was similar in both groups (p = 0.7), although infection was more severe with open harvesting. Pain score was lower (p = 0.006) with endoscopic harvesting.

CONCLUSIONS

Endoscopic radial artery harvesting was associated with better wound appearance and less pain. Occurrence of neurologic deficits and wound infection was infrequent in both groups.

Isoprostanes constrict human radial artery by stimulation of thromboxane receptors, Ca2+ release, and RhoA activation

OBJECTIVES

Radial artery vasospasm remains a potential cause of early graft failure after coronary bypass graft surgery, despite pretreatment with alpha-adrenergic or calcium channel blockers. We examined the roles of isoprostanes and prostanoid receptors selective for thromboxane A2 in the vasoconstriction of human radial arteries.

METHODS

Human radial arterial segments were pretreated intraoperatively with verapamil/papaverine or nitroglycerine/phenoxybenzamine, or not treated. In the laboratory, we measured isometric contractions in ring segments, vasoconstriction in pressurized segments, and changes in [Ca2+] and K+ currents in single cells.

RESULTS

Although phenoxybenzamine eliminated adrenergic responses, the isoprostane 15-F(2t)-IsoP and 2 closely related E-ring molecules (15-E(1t)-IsoP and 15-E(2t)-IsoP) still evoked powerful contractions; 15-E(2t)-IsoP was approximately 10-fold more potent than the other 2 agents. Responses were mediated through thromboxane receptors because they were sensitive to ICI-192605. Furthermore, they were sensitive to the Rho-kinase inhibitors Y-27632 or H-1152 (both 10(-5) mol/L) or to cyclopiazonic acid (which depletes the internal Ca2+ pool), but not to nifedipine. In single cells, 15-E(2t)-IsoP elevated [Ca2+]i and suppressed K+ current.

CONCLUSIONS

Isoprostanes accumulate after coronary artery bypass graft surgery, yet none of the currently available antispasm treatments for radial artery grafts is effective against isoprostane-induced vasoconstriction. It is imperative that more specific treatment strategies be developed. We found that isoprostane responses in radial arteries are mediated by prostanoid receptors selective for thromboxane A2 with activation of Rho-kinase and release of Ca2+. Pretreatment of radial artery grafts with Rho-associated kinase inhibitors may potentially reduce postoperative graft spasm. Clinical studies to test this are indicated.

Extrafascially harvested radial artery in CABG: technique of harvest, complications, and mid-term angiographic patency

BACKGROUND

The initial use of radial artery (RA) for myocardial revascularization was abandoned due to high incidence of early occlusion. The revival of radial artery graft use was attributable to the improved harvesting techniques as well as the introduction of antispasm prophylaxis by calcium channel blockers. Various techniques of harvesting RA have been described and extrafascial harvest is one of the techniques to minimize trauma during harvest. The immediate arm complications and mid-term angiographic patency of the radial artery grafts harvested using extrafascial no-touch technique and used as a conduit for myocardial revascularization were not documented well in the literature.

METHODS

Between January 1997 and February 2003, 385 patients were operated for coronary artery bypass grafting using radial artery graft as one of the conduits. We used extrafascial no-touch technique and a coagulation current cautery at a strength of 10 to 15 W to control the bleeding during the blunt dissection of the radial artery. The complications related to the radial artery harvest were prospectively recorded and analyzed. This conduit was used as a free graft in 272 patients, left internal mammary artery and radial artery Y graft in 61 patients, Right internal mammary artery, and radial artery composite in situ graft in 52 patients. The radial artery donor arm in these patients was evaluated for complications. Angiographic evaluation of the radial artery graft was carried out randomly in 51 patients and angiography was done after an interval of 6 to 72 months (mean 29.55 +/- 21.77 months).

RESULTS

In two patients, although the preoperative Allen test was negative, the radial artery was not harvested after completion of the dissection and was left in situ because the pulse could not be felt in the radial artery distal to the clamp after trial occlusion of the mid part of RA. The arm complications noticed were cutaneous parasthesias in 9 patients (2.33%), which subsided in 4 weeks, stitch abscess and superficial wound infection in 4 patients (1.03%), hematoma/seroma treated with drainage in outpatient department in 3 patients (0.78%), and wound infection requiring open drainage in an operating room in one patient (0.76%). Angiographically radial artery was patent in 48 of 51 patients (94.11%).

CONCLUSIONS

The extrafascial technique of radial artery harvest is safe and an easily reproducible method with minimal arm complications and good mid-term clinical and angiographic results. The mid-term angiographic patency rates of RA harvested using this technique are comparable to that of the published results of intrafascially harvested radial artery grafts and left internal mammary artery grafts.

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.

Can the Use of the Radial Artery Be Expanded to All Patients with Different Surgical Grafting Techniques? Early Clinical and Angiographic Results in 600 Patients

OBJECTIVE

The use of the radial artery (RA) as a conduit for coronary artery bypass grafting (CABG) is gaining in popularity worldwide and is being increasingly adopted by many cardiac surgeons. Encouraged by our satisfactory early experience with the use of the RA conduit, we have expanded its use to more than 90% of all coronary surgery patients. The aim of the present study was to review our clinical and angiographic results when the use of the RA conduit was expanded to all patients including those aged 65 years and older and diabetics with different surgical grafting techniques.

METHODS

The records of 600 consecutive patients who underwent isolated CABG using the RA graft at Harefield Hospital between January 1999 and August 2002 were reviewed retrospectively. Ninety-three (15.5%) patients consented and underwent angiography before discharge at the earliest on the fourth postoperative day, aiming to look at the quality of anastomoses and the patency of the RA grafts.

RESULTS

The 600 patients had 613 RA grafts to perform 652 distal RA anastomoses. The proximal ends of 515 (84%) RA grafts were anastomosed to the aorta, 98 (16%) RA grafts were constructed as Y-grafts with 49 (8%) RA off a vein graft hood, and 49 (8%) RA grafts were constructed as T- or Y-grafts off an internal thoracic artery (ITA) graft. The proximal ends of 19 (19/294 or 6.5%) vein grafts were constructed as Y-grafts off the RA grafts. Two hundred and sixty-one (43.5%) patients were above the age of 65 years and 111 (18.5%) patients were diabetics. There were four in-hospital deaths (0.6%) among the study patients. Six (1%) patients developed forearm hematoma/seroma postoperatively. The operation time, the hospital stay, and the incidence of conduit harvest site infection for the patients who had vein grafts in addition to the RA grafts were significantly higher than those of patients who had RA grafts only. On postoperative angiography, 86 out of 93 (92.5%) RA grafts were found to be patent with good quality distal anastomoses. The maximum stenosis of the coronary arteries bypassed by the patent 86 RA grafts was 82.6 +/- 6.2%, while it was 56.3 +/- 15.4% for the coronary arteries bypassed by the occluded seven RA grafts, p < 0.001.

CONCLUSION

The use of the RA can be expanded to all patients with different surgical grafting techniques and provides satisfactory clinical and angiographic outcomes.

Right internal mammary artery and radial artery composite in situ pedicle graft in coronary artery bypass grafting

BACKGROUND

The use of two internal mammary artery grafts in coronary artery bypass grafting has been associated with decreased risks of death, reoperation, and angioplasty. However, bilateral internal mammary artery takedown is associated with higher incidence of sternal wound infection, particularly in people with diabetes and in elderly and obese patients. This study was conducted to explore the feasibility of using right internal mammary artery (RIMA) and radial artery (RA) as a composite graft while preserving the distal two thirds of the RIMA to leave the sternal blood supply intact.

METHODS

Eighteen patients underwent coronary artery bypass grafting using proximal RIMA and RA composite graft as one of the bypass conduits. The distal two thirds of the RIMA was left intact to preserve sternal blood supply. The graft-free flows of the RIMA and RA composite graft and of the left internal mammary artery graft and the length of the composite graft had been measured. The graft patency and the flow in the distal part of the unharvested RIMA was evaluated postoperatively 2 weeks after the procedure. In 6 of these patients the graft patency was evaluated by selective angiography.

RESULTS

There was no hospital mortality or incidence of perioperative myocardial infarction. None of the patients needed intraaortic balloon pump support postoperatively. There was no sternal wound infection. The vessels grafted were distal right coronary artery (n = 7), posterior descending artery (n = 8), obtuse marginal branches (n = 3), and posterolateral ventricular branch (n = 1); 1 patient received the composite graft as a sequential graft to the posterior descending artery and posterolateral left ventricular branches. The mean graft-free flow of the RIMA and RA composite graft was 98.06 +/- 16.93 mL/min compared to left internal mammary artery flows of 55.80 +/- 8.99 mL/min. All 16 patients who had a good echo window showed patent grafts when evaluated by two-dimensional echocardiography and color Doppler echocardiography. All of the 6 patients in whom the angiogram was repeated postoperatively showed patent RIMA and RA grafts.

CONCLUSIONS

Myocardial revascularization using proximal RIMA and RA in situ pedicle graft was safe in patients with diabetes and in obese and chronic obstructive pulmonary disease patients. This graft was useful to revascularize posterior descending artery, posterolateral ventricular branches of right coronary artery, and obtuse marginal branches where a left internal mammary artery and RA composite graft cannot be used because of technical reasons. Its usage was not associated with sternal wound infection.

Does warm blood retrograde cardioplegia preserve right ventricular function?

BACKGROUND

Efficacy of warm blood retrograde cardioplegia in preserving right heart function remains controversial. The current study was conducted to gauge the preservation of right ventricular function after warm blood retrograde cardioplegia.

METHODS

We studied 75 consecutive patients undergoing isolated heart valve procedures with warm blood retrograde cardioplegia as the exclusive mode of preservation. Right ventricular radionuclide ejection fraction and hemodynamic measurements using a pulmonary artery catheter were calculated before and within 3 days after operation.

RESULTS

Postoperative radionuclide right ventricular ejection fraction was well preserved at 0.4686 +/- 0.0122 compared with 0.4327 +/- 0.0255 preoperatively (p = 0.7064). Right ventricular systolic work index improved from 5.82 +/- 0.52 to 8.97 +/- 0.60 g x m/m2 (p < 0.0001) and cardiac index increased from 2.40 +/- 0.09 to 2.92 +/- 0.11 L/m2 (p < 0.0001). When right ventricular systolic work index was correlated with preload, 30 patients moved up and down on the same ventricular function curve and 42 moved to a higher inotropic curve postoperatively. Only 3 patients demonstrated decreased inotropy.

CONCLUSIONS

In the clinical setting warm blood retrograde cardioplegia used as the exclusive mode of myocardial preservation provides adequate protection of the right heart.

Functional status of the hand after radial artery harvesting: results in 3,977 cases

BACKGROUND

The radial artery is being used as a conduit of choice over saphenous vein with increasing frequency. We analyzed early and midterm results of coronary artery bypass grafting using radial artery as one of the conduits. The functional outcome of the hand after radial artery harvesting was analyzed.

METHODS

The radial artery was used in 3,977 patients undergoing coronary artery bypass grafting between December 1996 and November 2000. Modified Allen's test was performed preoperatively in the ward and pulse oxymetry was used in the operating theater to assess the collateral circulation of the hand. A total of 4,172 anastomoses were performed using a radial artery. The patients were followed up at regular intervals in the outpatient clinic or were sent questionnaires. The functional results of the hand were assessed. Follow-up angiography was performed in 104 patients at a mean of 18 months.

RESULTS

The hospital mortality was 0.8%. Perioperative myocardial infarction occurred in 1.3% of patients. The average number of grafts was 3.12. No patient had acute ischemic injury of the hand. Follow-up was complete in 94% of patients. Late infection developed in 0.4% of patients. Numbness and paresthesias continued in 6.5% and 3% patients, respectively, after 3 months. The patency rate of the radial and left internal mammary artery was 92.3% and 96.0%, respectively, at a mean of 18 months.

CONCLUSIONS

Use of radial artery for coronary artery bypass grafting is associated with low morbidity and good functional outcome of the hand. It can be used more frequently as the conduit of choice after the internal mammary artery.

Does routine use of the radial artery increase complexity or morbidity of coronary bypass surgery?

BACKGROUND

Despite increasing data supporting its use, the uptake of radial artery coronary bypass grafting by most surgeons remains low. This may partly be from perceptions that it increases risk or complexity of coronary surgery.

METHODS

Data on 151 patients who had radial grafts are compared with 179 concurrent nonrandomized controls that underwent conventional surgery using saphenous vein. Additionally, telephone interviews were conducted on 127 radial recipients to assess subjective outcome.

RESULTS

Cardiopulmonary bypass and cross-clamp times were similar in both groups (72 versus 74 minutes and 20 versus 22 minutes). Morbidity was comparable (mortality 1% versus 2%; cerebral vascular accident 1% versus 2%; sternal infection 1% versus 2%; resternotomy 4% versus 6%). Of 127 patients contacted, 41 (32%) reported that they had experienced parasthesia, and 65 (51%) reported numbness related to radial harvest; of these, 75% reported their symptoms as resolved or resolving. Early angiography performed in 36 patients revealed a radial patency rate of 92%.

CONCLUSIONS

Concerns about increased morbidity and mortality should not hinder adoption of radial artery grafting.