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Seminars in
Thoracic and Cardiovascular Surgery James L. Cox, MD, Editor Vol 13 • No 1 • January 2001 • pp 38-41 Complex Valvular Procedures: Ross, Mitral, Redos — Time Enough?
John D. Oswalt, MD. The possibility of a lengthy ischemic time is considered when evaluating complex valvular procedures. This consideration or even worry may influence the choice of valve replacement, repair offered, or actual acceptance of the case because of expected outcomes. With the use of an integrated, streamlined blood cardioplegic delivery, we believe these complex valvular procedures, even combined with revascularization, can be managed with good results. Additionally, this technique allows for sufficient protection to teach these same complex valvular repairs. A summary of a 10-year personal experience with the Ross procedure in 120 patients is covered. Aortic stenosis, insufficiency, and, particularly, infective endocarditis, have been managed with an overall surgical mortality rate of 2.5%. The endocarditis subset has a mortality of 0% with 100% cure of the infection. Data regarding complex mitral repairs and replacement are likewise included. Key words: Complex valve procedures, Ross procedure, infective endocarditis, integrated-streamlined blood cardioplegia. 0ver the decades we have had great contributions to cardiac preservation. I have transitioned these years, adding and changing techniques based on principles that were sound and in keeping with the complexity of the procedures we were performing. Similar to 60% of cardiac surgery in the United States, this technique incorporates blood cardioplegia delivered both antegrade and retrograde in primarily continuous fashion. Our modifications have been primarily to simplify, while continuing to adhere to many of the basic principles of present day cardioprotection. A summary of these principles from antegrade blood cardioplegic, retrograde noncardioplegic blood perfusion, to warm reperfusion blood cardioplegia with the various substrates are discussed by Beyersdorf et al. [1] These investigators discuss and reference the basics for these techniques and justify their integration. Our modifications have simplified the types of cardioplegic solutions, streamlined the delivery system both for the surgeon and the perfusionist, and yielded excellent results clinically not only in the coronary revascularization patient but in those patients requiring complex valve repairs or replacements with and without impaired ventricles.
Methods The technique described is used in an 8-man group that practices at 5 different facilities. Standardization is complete among the surgeons, the perfusion group, and the various hospital sites. It is used on all patients whether revascularization, complex valvular procedure, or both. It is used by senior surgeons while teaching newer partners these difficult complex cases. This technique has also been implemented because I have traveled as a visiting surgeon teaching the Ross procedure. The cardioplegic solution is easy to produce, cost effective, and is prepared by the pharmacy of the respective hospitals and not purchased commercially (Table 1). The perfusionist’s job likewise is simplified by having a single liter bag of cardioplegic solution to begin the procedure. He will reuse that same liter bag to fill repeatedly for the cold retrograde blood perfusion. Initially, 400 mL of the cardioplegia is transferred to the surgical field (basin) for mixture with oxygenated blood to use as perfusate for completed venous revascularization grafts. In valve cases, this is not necessary. With the institution of cardiopulmonary bypass, 400 mL of oxygenated blood is removed from the oxygenator via the recirculation line.
This blood is mixed in the cardioplegic bag, which is at room temperature, and considered high K+. This bag is then placed in a blood administration pressure bag and suspended from an intravenous (IV) pole. The recirculation line runs in-line with an aluminum coil outside an iced bucket. The surgeon then connects the tubing from the cardioplegia bag to a Y perfusion catheter in the ascending aorta. With placement of the aortic cross-clamp, antegrade tepid blood cardioplegia is delivered at a pressure of approximately 150 mm Hg. A total of 500 mL is infused in all patients including those with aortic insufficiency. (The ventricle is not allowed to distend in patients with aortic insufficiency.) After the initial 500 mL, the tubing is switched to the retrograde catheter positioned in the distal coronary sinus and the remaining 500 mL is administered at 50 to 100 mL/min. Proper positioning of the retrograde catheter is very important and can be checked by visualizing a distended posterior ascending vein. On completion of the initial cardioplegic arrest, flow is interrupted as the same empty cardioplegic bag is refilled with oxygenated blood from the recirculation line. The aluminum coil is now immersed in an ice bath. Seven mEq KCL is then added to the liter and it is resuspended. The rate remains 50 to 100 mL/min of cold blood perfusate with low K+. Systemic temperatures are around 34°C. The perfusate is 4° to 10°C. This process is repeated until rewarming is begun. Serum K+ levels at the end of a usual case is 5.5 on average. Occasionally, if K+ rises, IV insulin is used. With rewarming, the coil is removed from the ice bath. As the oxygenated blood is warmed, so does the blood perfusate. The potassium keeps the heart relaxed. Should the continuous retrograde perfusion need to be stopped intermittently for visualization, the perfusionist stops the flow, not the surgeon. Often this allows for remixture, which takes a total of 2 minutes or less. At no point after the initial switch from antegrade to retrograde does the surgeon interrupt what he is doing for cardioplegia matters. This simplification likewise minimizes the amount of tubing and cannulae cluttering the surgical field. On release of the cross-clamp, rapid resumption of contractility is seen. The remaining minutes of bypass are spent ensuring hemostasis, gradually loading the ventricles, and placing pacing wires. Bypass is discontinued promptly. Obviously this technique can be used with all types of cases whether single two-stage cannulae in the atrium (all aortic cases) or bicaval cannulation (all mitral cases). We use the Guiraudon incision for almost all mitral valve complex repair cases. Results Over a 10-year period, a personal series of 120 Ross procedures have been performed in 92 men and 28 women with ages ranging from 17 to 67 years (mean 47 years). The diagnoses were stenosis, insufficiency, and mixed disease, with a particular subset of 23 patients with aortic infective endocarditis. An example of implementation is described in a high-risk patient with endocarditis. This particular patient was 47 years of age with both aortic and mitral annular abscesses and a ventricular septal defect (VSD). He was on chronic renal dialysis and infected with Staphylococcus aureus. Appropriate antibiotics were instituted and following after hemodialysis he was taken to the operating room in a hypotensive state. Transesophageal echocardiography (TEE) showed 4+ aortic insufficiency, 3+ mitral regurgitation, and a questionable VSD. Bicaval cannulation was used and the simplified integrated blood cardioplegic technique was used. Continuous retrograde perfusion was interrupted during completion of the autograft harvest from the posterior muscular bed and for left coronary ostial implantation. Otherwise, it was continuous. The aortic annular abscess encompassed three-fourths circumference of the annulus and extended into the septum with a small VSD and also into the posterior mitral annulus. The arrested heart was easy to debride. Complete debridement is paramount to success for infection eradication. The entire posterior mitral annulus was debrided and reconstructed with autologous pericardium. The excised mitral leaflet was extended likewise with pericardium. The annuloplasty ring was also pericardium as was the patch for the now larger VSD after debridement. The autograft made an excellent supple, viable valve for replacement. It conformed well at all levels of the debrided root as well as to the different tissues, muscle, annulus, and pericardium. The pulmonary homograft was implanted under cross-clamp. This patient was weaned from cardiopulmonary bypass (CPB) after 200 minutes of cardioplegic arrest. He was in sinus rhythm on lowdose dobutamine. His infection was cured and his length of stay (LOS) was 7 days. He continued on antibiotics as an outpatient for 6 weeks. The endocarditis patients in this series have 0% mortality with 100% eradication of infection and 100% freedom from reinfection. My individual Ross series has surgical mortality rate of 2.5% with an actuarial survival rate of 95%. 
Our group series of Ross procedures numbers 194 patients (Fig 1). Included in Figure 2 is a summary of the most recent 2 years of complex mitral valve repairs or replacements denoting age, sex, concomitant surgery, use of intra-aortic balloon pump (IABP), and mortality. Discussion The cardioprotective technique that we use is an amalgamation of ideas from methods proven to yield good clinical results. It is a simplified integrated system useful in all types of cardiac surgery. Antegrade delivery is chosen first because it allows for distribution most completely to the myocardium. In all cases, other than aortic insufficiency, rapid cardioplegia and arrest is achieved with the initial 500lmL bolus. We do use antegrade also for patients with aortic insufficiency, believing that high K+ cardioplegia is best distributed initially via the right coronary arterial system.[2] Preventive distention of the left ventricle is important so infusion to the subendocardial myocardium is complete. If arrest is not achieved with the antegrade, it is shortly achieved when the retrograde infusion is begun. The advantage to retrograde delivery is that it can be continuous or interrupted. In either case, the surgeon does not have to interrupt his focus to change back to antegrade or manipulate catheters in the coronary ostia. It is important to have the retrograde catheter positioned appropriately so that perfusion is distributed to the right ventricle. Our choice for retrograde is to run it continuously. There are times when it may be important to interrupt flow harvesting the autograft while dissecting around the 1st septal perforator or during the anastamosis of the left coronary ostium and during coronary anastamoses while doing bypass grafts. At no point during mitral valve cases do we stop the retrograde perfusion. After harvesting of the pulmonary autograft, bleeding points in the right ventricular muscular bed are easily identified by the resumption of the retrograde perfusion. These bleeding points are thoroughly controlled before ever completing the implantation of the pulmonary homograft. 
Temperature of the blood cardioplegia and perfusion is also varied in an integrated and simplified fashion. The integration is seen by a smooth transition from room temperature (tepid) induction both in antegrade and retrograde fashion followed by smooth transition to cold blood retrograde perfusate. As rewarming occurs, the perfusate then warms with the pump blood to deliver warm blood perfusion just before removal of the cross-clamp. Room temperature induction reduces the chances of reperfusion injury, particularly in those complex cases that may have ischemic injury or coronary disease in addition to valvular disorders. As mentioned earlier, the entire group believes this streamlined protocol is best for all cases including those requiring only revascularization.[3] After initial arrest, the relaxed myocardial protection is maintained via cold blood retrograde perfusate. It is delivered continuously so collateral mediastinal blood flow has little chance to rewarm the heart. The continuous cold retrograde perfusion maintains right ventricular (RV) and septal hypothermia to reduce demands and thereby overcomes limited retrograde RV and septal perfusion. Topical hypothermia is not used because it only serves to interrupt the surgical procedure or add another pad or device in the pericardial cavity to limit visibility. With proper positioning of the retrograde catheter in the coronary sinus, the right ventricular temperature remains low and protected. The cold blood perfusion is mandatory to maintaining an arrested heart. With 3 to 5 minutes of cross-clamp time remaining, the coil is removed from the ice bath and rewarming occurs. This warm retrograde perfusion maximizes adenosine triphosphate (ATP) replenishment and the arrested heart beats shortly after the removal of the cross-clamp. Our simplification does not require the addition of another cardioplegic solution and does not require reconnection to the antegrade catheter for the delivery of such new substrate.[4,5] Throughout the entire arrest period, the perfusionist has a single job that is repetitive and easily performed. Complex valve procedures with prolonged cardioplegic arrest can be operated with good results. Our cardioplegic techniques likewise allow for sufficient time to teach visiting surgeons these complex procedures. At Ross symposia or as a visiting surgeon, I have had adequate time to explain the difficult parts of the Ross procedure with beautiful exposure and with little concern for the arrest time. The integrated blood cardioplegic system allows for as much time as necessary to guide a surgeon through his/her first autograft harvest. All patients during these teaching cases have weaned from CPB without the use of heavy inotropes or IABP. Because of the integrated system, we felt confident in using the Ross procedure for infective endocarditis. These mostly normal ventricles in younger patients would not be harmed. This allowed us to choose the best surgery. Although extensive for the patient’s age, an excellent cure rate has been achieved with less chance for reoperation. In summary, a simplified integrated blood cardioplegic system using antegrade and retrograde perfusion in a streamlined fashion has yielded excellent myocardial preservation. It is delivered initially at room temperature, followed by cold perfusion, and finally by warm perfusion. Its use allows for repair of complex valvular problems with good visualization and rapid restoration of myocardial function after reperfusion. A 10-year series of Ross procedure patients, as well as a short-term report on complex mitral procedures, supports the system’s use. Acknowledgment I want to thank Suzi Nelson, RN, for her assistance in the preparation of this article. References
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