Tehnique for Using Soft, Flexible Catheter Stents in Aortocoronary Vein Bypass Operations

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1 Tehnique for Using Soft, Flexible Catheter Stents in Aortocoronary Vein Bypass Operations Louis G. Ludington, M.D., George Kafrouni, M.D., Merle H. Peterson, M.D., Joseph J. Verska, M.D., G. Arnold Mulder, M.D., and Lyman A. Brewer, 111, M.D. ABSTRACT A technique using soft, flexible catheter stents in performing coronary vein bypass surgery is presented which makes small vessel anastomoses easy and assures accuracy of suture placement with clear identification of the vessel lumen and an anastomosis without stenosis. It provides an essentially bloodless field without having to cross-clamp the aorta. The technique has been used to our complete satisfaction in all patients since we first started vein bypass operations in A review of the last 205 elective aortocoronary bypass grafts in 100 consecutive patients using this technique reveals a mortality of only 1% and an operative and postoperative myocardial infarction rate of 5%. About half the patients had left ventricular dysfunction with elevated end-diastolic pressures, and 68% had had previous myocardial inf arctions. Seventy percent of the patients are at present asymptomatic, 24% are improved, and only 4% show no improvement over their preoperative status during follow-up of one to three and one-half years. Soft, flexible catheter stents have been employed during aortocoronary vein bypass operations, simplifying small vessel anastomoses and assuring accuracy of suture placement, clear identification of the lumen, and an anastomosis without stenosis. An essentially bloodless field is achieved without cross-clamping the aorta. This technique has been used since our first patient, in February, 1970, and was adapted from a similar method used by one of us for many years in peripheral vascular vein bypass operations. Previous authors have described using graduated probes or Fogarty biliary catheters [l, 21 to achieve similar ease of anastomosis, but we From the Department of Thoracic and Cardiovascular Surgery, White Memorial Medical Center, Los Angeles, CA. Accepted for publication June 25, Address reprint requests to Dr. Ludington, Department of Thoracic & Cardiovascular Surgery, WhiteMemorial Medical Center, 1720 Brooklyn Ave, Los Angeles, CA believe soft, flexible catheters are easier to handle and are not so likely to traumatize the coronary arteries. The technique has been used to our complete satisfaction in all patients since coronary vein bypass operations were initiated at this institution. A recent review of 205 elective coronary vein bypass grafts in 100 consecutive patients using this technique reveals a mortality of 1% and a 5% incidence of electrocardiographically documented postoperative myocardial infarction. Surgical Technique Through a median sternotomy approach and after heparinization (3 mg per kilogram of body weight), the patient is put on partial cardiopulmonary bypass, usually using only one No. 40 venous cannula in the right atrium and a No. 18 to 24 aortic cannula. The left ventricle is vented with a cannula placed either through a pledget pursestring suture at the apex, as was done in our early experience, or, as is now usually the case, through the left atrium, either at its apex between the superior vena cava and aorta or through the superior pulmonary vein, passing through the mitral valve into the left ventricle. The patient is cooled to about 32 C and then the heart is electrically fibrillated. The saphenous vein is harvested atraumatically from the leg by a second team. The vein here is smaller and more appropriate in size, and we find healing of the wound incision better, with less scarring and less tendency to infection as compared to vein from the thigh area. No clamps are used on the vessel, the adventitia is not stripped, and tributaries are cut long enough so that ligatures do not kink or narrow the vein. Usually harvesting the vein and placing the patient on cardiopulmonary bypass take the two teams about the same length of time. A small pediatric 5F argyle catheter (Fig 1) is threaded through the vein in a reverse direction. 328

2 329 Ludington et al: Soft Flexible Catheter Stents in Coronary Bypass Fig 1. Six 3.5 orid 5F soft, fle.xible argyle catheters. Heparinized blood is injected at intervals during threading of the catheter to check for leaks. When the vein has been thoroughly tested, the catheter is passed completely through it (Fig 2). These argyle catheters are soft and pliable and have a smooth tip that will not traumatize or damage the vein or coronary artery. The - 3.5F catheter fits nicely into the circumflex, marginal, anterior descending, or diagonal branch of the left coronary artery system, while the 5F size usually fits nicely into the right coronary artery. We generally do the right coronary artery anastomosis first, often while the heart is still beating and before starting partial cardiopulmonary bypass, if the vessel is large and not too sclerotic or calcific at the anastomotic site chosen. If the vessel is small or of poor quality, then the left ventricular vent is put on suction and the Fig 2. Vcirryr~7ft?Pith irrtrnlirriiirral catheter. heart is electrically fibrillated to create a quiet field for greater accuracy. Very little retraction of the heart is required to do the right coronary artery anastomosis, even at the crux or in the posterior descending or left ventricular branch, so this anastomosis can be started while the patient is being stabilized on cardiopulmonary bypass. Also, the first segment of the vein to be used is larger and corresponds better to the large right coronary artery. An arteriotomy incision is made at a chosen site on the right coronary artery where the wall is soft and beyond the stenotic plaque or obstruction. The catheter slides easily through this arteriotomy distally into the artery, occluding it and preventing back-bleeding. A second argyle catheter, size 3.5 or 5F depending on the degree of stenosis, is passed retrograde to prevent forward bleeding (Fig 3). Sometimes traction sutures are placed around the coronary artery above and below, with a soft rubber snubber to control bleeding if the stents do not fit snugly. (If the right coronary artery is completely occluded, the second catheter can be dispensed with.) With the two stent catheters in place, in a relatively bloodless field, and with the vein graft already trimmed to form a hood of appropriate size, three interrupted 7-0 Prolene sutures are placed at each angle of the arteriotomy and through the vein as shown in Figure 3. These interrupted sutures are placed at these two most critical areas under careful direct vision, with the stents making visualization of the lumen and of the vein and artery lips easy (see Fig 3). Now the Fig3. Catlietersterits iii distal oridprosirrznl arten/ arid cororinry sirtiires iii place. INTRALUMINAL CATHETER VEIN WITH BEVELED HOOD READY FOR ANASTOMOSIS VEIN VALVE VEIN VEIN VALVE INTRALUMINAL VEIN CATHETER. PASSED INTO DISTAL CORONARY ARTERY 3 INTERRUPTED CORNER SUTURES AT EACH END READY FOR TYING c STENOTIC PLAQUE WITHIN CORONARY CATHETER PASSED RETROGRADE TO STENOTIC PLAQUE

3 330 'The Annals of Thoracic Surgery Vol 21 No 4 April 1976 second suture from each corner on one side is run toward the midline and tied, completing the anastomosis on that side. Thisusually takes only one to three running sutures from each end. The second suture from each direction on the opposite side is then run in the same manner (Fig 4). The catheter passing retrograde up the right coronary artery is removed before the last few sutures are placed. By this time both the upper and lower running suture can be put on gentle traction to pull the artery and vein lips together, stopping the bleeding that occurs on removal of the catheter and making placement of the final sutures easy (Fig 5). The same technique is used on the circumflex or marginal branch. We like to do these anastomoses second because by now the patient is well stabilized on cardiopulmonary bypass with a good mean blood pressure, and the heart can be retracted to expose these more inaccessible vessels with less likelihood of a blood pressure drop. Usually the 3.5F catheter is needed in these small vessels, which vary from 1.5 to 3 mm in size. We do the anterior descending or diagonal branch last, using the same technique and the same 3.5F catheter. On completing each anastomosis, the catheter stent passing through the vein into the distal artery is removed to allow blood to flow retrograde and completely fill the vein. As the catheter is pulled back, blood fills the anastomotic site so it can be checked for any evidence of leaks (see Fig 5). After the distal right coronary artery anastomosis is completed, the vein is cut to the appropriate length for the aortic anastomosis. The Fig4. Anastomosis completed and catheterstents ready for withdrawal before final sutures areplaced. CATHETER REMOVED PRIOR TO FINAL SUTURES AND TIE Fig5. Retrograde catheter out and intraluminal catheter withdrawn beyond first valve, showing good retrograde filling of veingraft. STENOTIC PLAOUE WITHIN CORONARY ANASTOMOSIS NOW COMPLETE AND DISTENDED TO CHECK FOR lag next portion of the vein, with the intraluminal stent, is then used for the circumflex or marginal bypass. After these anastomoses, the stent is again withdrawn for back-bleeding and the anastomosis is checked. The vein is again cut to the right length for the aortic anastomosis. The remaining portion of vein is then used for the anterior descending or diagonal coronary artery unless an internal mammary artery bypass is to be done. This permits using that part of the vein with the smallest lumen for the anterior descending bypass, which contributes to more rapid flow. After all distal anastomoses have been completed and checked as described, the heart is rewarmed. We like to start rewarming during the last distal anastomosis. The aortic anastomoses are carried out by cutting small divots from the ascending aorta with a No. 12 or 11 blade scalpel or with a punch after placing a partially occluding clamp on the ascending aorta. Here the anastomosis is performed with a double-needle 6-0 Prolene suture with a 5 or 8F catheter stent in the vein to make handling easier, holding the lips apart and assuring a good-sized anastomosis without stenosis. The stent also prevents back-bleeding if the valves in the vein are not competent. After placement of the inferior suture, the sutures are run up each side and the catheter stent is removed before the final sutures are placed. As the vein stent is slowly pulled out, the entire vein fills with blood, removing all air. If the catheter is withdrawn too rapidly, some of the valves may be-

4 331 Ludington et al: Soft Flexible Catheter Stents in Coronary Bypass come competent and prevent complete filling of the veins, resulting in incomplete evacuation of air. If air remains in any of the vein grafts when the partially occluding clamp is removed, it is allowed to leak out through the needle holes of the anastomosis as the vein grafts are occluded digitally or with Fogarty rubber-shod clamps. Sometimes it is necessary to aspirate air from one or more of the bypass grafts with a No. 27 needle. It takes us about 30 minutes to do a double distal anastomosis and about 45 minutes for a triple. We like to discontinue bypass once the patient is rewarmed and before doing the proximal anastomoses if left ventricular function is adequate. If left ventricular function is poor, we usually have to wait until the heart is completely revascularized, with the vein bypass grafts functioning, to allow the left ventricular myocardium to receive the maximum oxygenated blood to sustain itself without assistance. When all anastomoses are completed, the patient is off the pump and decannulated, and all bleeding is controlled, the chest is closed in routine fashion. Two mediastinal argyle catheter drains are placed through stab wounds in the epigastrium. One, a No. 36 straight, is placed in the anterior mediastinum, and the second, a No. 32 right-angled, is placed in the pericardial sac. If either pleural space has been breached, the upper end of the straight mediastinal catheter is placed in the pleural space at the apex to provide air drainage of the pleural space as well as serosanguineous drainage from the anterior mediastinum. Clinical Experience in 100 Patients The criterion for operation in all patients was angina pectoris with angiographic evidence of 70% or more stenosis of one or more proximal coronary arteries with fair to good distal runoff. Seventy-nine patients were men and 21 were women. The age range was 37 to 82 for men and 30 to 73 for women; the average age for both was 56 years. Stable angina was present in 24 patients, 60 had unstable or accelerated angina, and 10 had intermediate or preinfarction angina. Sixty-eight patients had sustained previous myocardial infarctions. Associated dyspnea on exertion was present in 28 patients and evidence of mild congestive heart failure in 11. Seventyfive of the patients were in NYHA Functional Class I11 or IV (Table 1). About half of the patients had evidence of left ventricular dysfunction and abnormally high left ventricular enddiastolic pressures. For vessel involvement encountered angiographically see Table 2, and for risk factors see Table 3. A total of 205 bypass grafts were constructed in these patients: 22 single bypasses (with 2 internal mammary artery bypasses), 51 double bypasses (with 2 Vineberg implants), and 27 triple bypasses. Among the grafts in which flow was measured, 70 to the right coronary artery had average flow rates of 77 mlimin; the 81 grafts to the left anterior descending coronary artery had an average flow rate of 69 mlimin; and flow in the 51 grafts to the circumflex coronary artery and its branches was 61 mllmin. Complete re- Table 1. Cardiac Status of 100 Patients Cardiac History Myocardial infarction Angina patterns Single severe attack Stable angina Increasing angina Intermediate or preinfarction syndrome NYHA Functional Class I1 111 IV Dyspnea on exertion Congestive heart failure LM = left main equivalent. 68 (3 acute) 6 (2 LM disease) Table 2. Angiograpkic Evidence of Disease in 100 Patients No. of No. of Disease Patients Disease Patients RCA 81 One-vessel 12 Left main 7 Two vessel 23 LAD 90 Three-vessel 65 Circumflex 66 Marginal 13 LV dysfunction 49 Diagonal 11 LVH 36 KCA = right coronary artery; LAD = left anterior descending coronary artery; LV = left ventricular; LVH = left ventricular hypertrophy.

5 332 The Annals of Thoracic Surgery Vol 21 No 4 April 1976 Table 3. Coronary Disease Risk Factors in 100 Patients Risk Factor Hypertension Lipid abnormalities Diabetes mellitus Smoking Obesity Positive family history Other risk factors present Ulcers Gallbladder disease Previous CVA CVA = cerebrovascular accident known 4 newly discovered 5 incipient (+ 13 slightly) vascularization was done in 59 patients, incomplete revascularization in 41. The operative mortality was 1% and the percentage of operative and postoperative myocardial infarctions was only 5%; Table 4 gives a complete list of complications and mortality. The median postoperative hospitalization time was 11 days with a range of 8 to 33 days. Of interest are those risk factors present in patients who had a slow recovery. They were: Sex-slower recovery in women Obesity Diabetes mellitus Congestive heart failure preoperatively NYHA Class IV Angina at rest Triple-vessel disease Triple-vessel bypass Cardiopulmonary bypass time longer than two hours Table 4. Complications in 100 Patients Complication Bleeding 5 (2 reop) Dehiscence 3 (2 reop) Wound infection 3 MI postoperatively 5 (1 death, 2 slow recovery, & Arrhythmias 2 late deaths) VF or VT 3 Afiblflutter 8 PVC or PAC 24 BUN over 50 mg/loo ml 7 (1 peritoneal dialysis) Pulmonary embolus 2 Early graft failure 2 (1 reop, survival, & 1 death ) Failure requiring 2 (1 deatha) balloon assist Hepatitis -- 2 =Same patient. MI = myocardial infarction; VF = ventricular fibrillation; VT = ventricular tachvcardia; PVC = premature ventricular contraction; PAC = iremature atrial contraction; BUN = blood urea nitrogen. Follow-up survey shows 70% active without angina, 24% active with occasional or decreased angina, and 4% with no improvement. There has been a 3% late mortality including 2 deaths from myocardial infarction and 1 late death from carcinoma of the jaw in the one to three and one-half years follow-up of these 100 patients. References 1. Grow JB Sr, Brantigan CO: Use of a Fogarty biliary catheter to create a bloodless field for saphenous vein-coronary artery anastomosis. J Thorac Cardiovasc Surg 68: 105, Parsonnet V, Gilbert L, Gielchinsky I: Graduated probes for coronary bypass surgery. J Thorac Cardiovasc Surg 68:424, 1974