S (AVR) for calcareous aortic stenosis, one of the most

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1 Ultrasonic Decalcification of the Aortic Annulus During Aortic Valve Replacement Barry B. Sheppard, MD, Jeffrey C. Milliken, MD, Ronald J. Nelson, MD, David M. Follette, MD, and John M. Robertson, MD Departments of Surgery, Harbor/UCLA Medical Center, Torrance, and Saint John s Hospital and Health Center, Santa Monica, California Aortic valve replacement for calcific aortic stenosis re- seating of the valve, and may allow placement of a larger quires meticulous debridement of the aortic annulus to valve. Our follow-up ranges from to 3 months (mean effect optimal valve seating. Since 987, we have used follow-up, 9 months) with 0% incidence of paravalultrasonic energy to debride the aortic annulus during vular leak or valve failure. We advocate the use of aortic valve replacement in 56 patients. In our experi- ultrasonic debridement as an adjunctive tool in aortic ence, ultrasonic debridement of the annulus is superior valve replacement. to traditional methods of debridement, affords improved (Ann Thorac Surg 99;5:59-65) ince the introduction of aortic valve replacement S () for calcareous aortic stenosis, one of the most technically demanding aspects of the operation has been the management of the calcified annulus. Excising the maximum amount of calcific tissue without injuring the annulus, aortic wall, or underlying ventricular septum has always been challenging. However, proper seating of the replacement valve is dependent on removing excess tissue without weakening the surrounding structures. Until now, this has required surgical excision of the aortic valve followed by sharp dissection or piecemeal removal of the remaining calcific cusp and annular calcium with scissors, scalpel, rongeur, or forceps. Once this was accomplished, the surgeon faced further difficulty placing sutures into areas of deeply seated annular calcium or the risk of fraying sutures on sharp calcific edges. Since 987, we have used the Cavitron ultrasonic surgical aspirator (CUSA) (Cavitron Surgical Systems, Inc, Stamford, CT) to debride the aortic annulus after aortic valve excision and have found that it easily removes annular calcium, thus returning the annulus to a pliable, more normal state. This has greatly facilitated aortic valve replacement in the setting of calcific aortic valvar disease. The CUSA was initially developed for use in neurosurgical procedures. It is an ultrasonic device, which vibrates at 3,000 cycles per second in association with an irrigation/suction tip. The ultrahigh-frequency vibrations dislodge calcium from adjacent softer tissues, which are more able to absorb the vibration energy. Recently, the CUSA has been applied to the arena of cardiac surgery in decalcifying aortic [l-5 and mitral [I, 6 valves. We have used it since 987 in to decalcify the aortic annulus before seating the replacement valve. This practice was prompted by our dissatisfaction with previous methods of Accepted for publication Feb, 99. Address reprint requests to Dr Robertson, HarborlUCLA Medical Center, 000 W Carson St, Torrance, CA debriding the aortic annulus. Use of the CUSA has greatly facilitated by () debriding excess calcium from the annulus, () providing a pliable aortic annulus that more easily accepts and conforms to the replacement valve, and (3) preserving the basic anatomy of the aortic root and annulus, whereas sharp dissection can remove soft tissue, which is saved by the ultrasonic technique and is valuable in securing the sewing ring. Material and Methods We performed our first CUSA-assisted on vember, 987, at Harbor/UCLA Medical Center, Torrance, CA. Since that date, we have used the CUSA to ultrasonically debride the annulus during 56 s at either Harbor/UCLA Medical Center or St. John s Medical Center, Santa Monica, CA. The charts of the 56 patients were reviewed for age, sex, primary and secondary diagnoses, operation performed, heart catheterization data, length of hospitalization, and postoperative complications. The operative reports were reviewed for the type of valve used as well as cardiopulmonary bypass and aortic cross-clamp times. Also recorded were the results of postoperative echocardiography, when performed, to determine postoperative valve function and incidence of paravalvular leak. Follow-up was obtained from the patients cardiologists and internists. When there was no clinic visit within the past 6 months, the patient was contacted for follow-up data. During each operation, the aortic valve was excised using a standard technique. A strip of moistened gauze (half of a standard 4 x 4 gauze sponge) was placed into the left ventricle to catch any loose, debrided calcified tissue that might escape the suction tip of the CUSA. The CUSA was then used on the annulus to break up and remove all major calcified deposits (Figs -5). Care was taken to avoid the introduction of any debris into the coronary ostia; this was not difficult because the suction 0 99 by The Society of Thoracic Surgeons /9/$3.50

2 60 SHEPPARD ET AL Ann Thorac Surg 99;5:594 Fig. (This and all subsequent figures are of patient 55.) Heavily calcified bicuspid aortic valve. Fig 3. Beginning of annular decalcification using probe of Cavitron ultrasonic surgical aspirator. tip of the CUSA probe adequately retrieved almost all of the loosened material. (We found the use of an additional neuro-tip sucker by an assistant helpful in minimizing debris.) The operating surgeon determined the adequacy of decalcification by palpation of the annulus. Once this was accomplished to the satisfaction of the surgeon, the annulus was sized and the replacement valve chosen. Valves were seated using interrupted -0 pledgeted Tevdek sutures in a single-plane fixation technique (Fig 6). Fixty-six patients underwent ultrasonic decalcification with the CUSA during (Table ). There were 4 men and women. The average age was 66? years with a Fig. Aortic valve annulus after cusp excision demonstrates heavy calcific deposits in the remaining annular tissue (tip of forceps). Fig 4. Probe being used to remove last bits of deeply seated calcium in the aortic annulus. (te gauze sponge in the left ventricular cavity to collect any loose debris that might escape suction tip of the aspirator.)

3 Ann Thorac Surg 99;59-6 SHEPPARD ET AL 6 range of 3 to 85 years. Mean preoperative hemodynamic values are shown in Table. The operations performed included 37 single s, s with concomitant coronary artery bypass grafting, repeat s, with mitral valve commissurotomy, one with mitral valve replacement, with mitral valve replacement and tricuspid valve annuloplasty, and with repair of intraoperative aortic dissection. The replacement valves employed included St. Jude prostheses, 0 Carpentier- Edwards porcine valves, and Hancock porcine valve. The mean aortic cross-clamp time for all procedures Wac 99 t 7 minutes, and the mean time on cardiopulmonary bypass was t minutes. The mean cross-clamp and cardiopulmonary bypass times for single were 88 minutes and 6? 6 minutes, respectively. An intraaortic balloon pump was necessary in only patient. The mean postoperative hospital stay was t 9 days with a range of 5 to 64 days. Early and Late Deaths One early and 3 late postoperative deaths have occurred in the series. The early death involved a 64-year-old man who sustained an embolic stroke days after discharge home (patient ). The patient was admitted to the intensive care unit and received a heparin sodium drip. There was marked worsening of his respiratory status, and a repeat computed tomographic scan of the head revealed a massive intraparenchymal bleed with mass effect and threatened uncal herniation. The patient died after respiratory support was withdrawn at the request of the family. The first late death was a 77-year-old man found dead at his home year after the cardiac operation (patient ). postmortem examination was performed, and the Fig 5. Aortic annulus after decalcification with the Cavitron ultrasonic surgical aspirator. Fig 6. Aortic annulus with seated St. Jude valve prosthesis. cause of death is unknown, although his last cardiac examination was unremarkable. The second late death involved a 6-year-old man with chronic obstructive pulmonary disease who died of pneumonia months postoperatively (patient 7). The third late death was a suicide by a 64-year-old physician 3 months postoperatively (patient 9). He was without cardiac symptoms at the time of death. This death was not calculated into the late mortality rate, as it was a suicide. The -day operative mortality rate was thus % and the late postoperative mortality rate, 4%. Postoperative Complications Excluding atrial arrhythmias, which were present in of the 56 patients, there were 3 postoperative complications in patients (Table 3). All of the arrhythmias, both atrial and ventricular, were controlled with medication. The two cerebrovascular accidents were both transient neurological events, and neither patient had a measurable residual deficit at the time of follow-up. Two of the three conduction defects, a right bundle-branch block and a complete heart block, resolved without treatment during the patients hospitalizations. The third conduction defect, a :l block in a patient with severe pulmonary hypertension and complex arrhythmias, was eventually converted to a stable atrial fibrillation rhythm. In the case of the patient with a perioperative myocardial infarction, which was diagnosed by electrocardiographic and enzymatic evidence immediately postoperatively, the postoperative course was not adversely affected, and the patient was discharged home on the eight postoperative day. Postoperative echocardiography was performed in (7%) of the 56 patients. All of the valves were functioning well when studied. ne of the patients studied had evidence of a paravalvular leak.

4 6 SHEPPARD ET AL Ann Thorac Surg 99;5:594 Table. Patients Undergoing CUSA-Assisted Aortic Valve Replacement LVEDP Patient Age PASP PADP (mm Gradient Areab. (y) Sex Diagnosis Operation Valve (mm Hg) (mm Hg) Hg) (mm Hg) (cm3) Secondary Diagnoses M AS M AS M AS M AS,MS 76 M AS 67 M Ventricular failure 76 M AS 63 M AS,CAD 64 M AS 76 F AS 57 M AS 50 F AS 64 M AS 70 M A 7 M AS 70 M AS, A 79 F AS,CAD 6 F AS,CAD 8 F AS, A 70 M AS, CAD 85 F AS 56 M AS 6 F AS 76 M AS 60 M AS, A 58 M AS,CAD 59 M AS,CAD 63 M AS 5 M AS M AS, A 64 M AS 8 F AS, CAD 8 F AS, MR 79 M AS,CAD 76 M AS,CAD 75 M AS,CAD 59 M AS,CAD, MVC Redo, CABG Redo, CABG, CABG, ADR, CABG, CABG, CABG, CABG, CABG, CABG, CABG, CABG TIA 0.90 CHF, sarcoid CHF, Htn, COPD Ventricular ectopy PUD, hepatitis B 0.50 Htn, CHF, SBE Htn, COPD s/p angioplasty DM CAD, atrial fibrillation, BPH DM, PUD, CVA, Parkinson s/p valvoplasty Htn, MI, anemia Atrial fibrillation ESRD, COPD, CHF, prostate cancer Hypothyroid, alcoholism Htn CHF, COPD, Htn Bladder cancer Htn, arthritis Hypothyroid coagulopathy CHF, atrial fibrillation Obesity CHF, COPD CAD, Htn, PVD, s/p CABG COPD, Htn COPD CHF CHF, pulmonary Htn CHF, angina Diverticulitis DM, asthma, prostate cancer, CHF BPH Angina Angina, Htn, hypercholesterolemia

5 Ann Thorac Surg 99;59-6 SHEPPARD ET AL 63 Table. Continued LVEDP Patient Age PASP PADP (mm Gradient Areab NO. (y) Sex Diagnosis Operation Valve (mm Hg) (mm Hg) Hg) (mm Hg) (cm3) Secondary Diagnoses AS 8 F AS, A 75 F AS 63 F AS, MS 63 F AS 76 F AS 78 F AS, MR 58 M AS,CAD 57 M AS 73 M AS 3 M AS, A 66 M AS 76 M AS,CAD 77 M AS, MVR, CABG, MVR, TVA, CABG CAD, COPD, Htn, PUD CAD, PVD Atrial fibrillation, COPD, CVA Breast cancer Hypercholes terolemia Htn, CHF, RI A CHF, pleural effusion MS, TI, pulmonary Htn CHF, BPH, COPD Hypothyroid, renal cancer DM, Htn, s/p CABG a This is the mean aortic valve gradient. This is the aortic valve area. ADR = aortic dissection repair; A = aortic insufficiency; AS = aortic stenosis; = aortic valve replacement; BPH = benign prostatic hypertrophy; CABG = coronary artery bypass grafting; CAD = coronary artery disease; C-E = Carpentier-Edwards; CHF = congestive heart failure; COPD = chronic obstructive pulmonary disease; CVA = cerebrovascular accident; DM = diabetes mellitus; ESRD = end-stage renal disease; Hk = Hancock; Htn = hypertension; LVEDP = left ventricular end-diastolic pressure; MI = myocardial infarction; MR = mitral regurgitation; MS = mitral stenosis; MVC = mitral valve commissurotomy; MVR = mitral valve replacement; PADP = pulmonary artery diastolic pressure; PASP = pulmonary artery systolic pressure; PUD = peptic ulcer disease; PVD = peripheral vascular disease; RI = renal insufficiency; SBE = subacute bacterial endocarditis; SJ = St. Jude; slp = status post; TI = tricuspid insufficiency; TIA = transient ischemic attack; TVA = h-icuspid valve annuloplasty. Follow-up Only patient was completely lost to follow-up. She was admitted to a nursing home soon after operation, and her primary physician retired, causing her records to become unobtainable. Of the other 5 patients, 4 are considered to have limited follow-up, as they have not been evaluated within the past 6 months. Their follow-up ranged from month to months with a mean of 6 f 5 months. Forty-seven patients have current follow-up as defined by office visit or telephone contact within the past 6 months, and their follow-up ranged from to 3 months with a mean of f 9 months. They are currently without clinical evidence of paravalvular leak or valve malfunction. There were 4 deaths. Therefore, follow-up is complete for 5 (9%) of the 56 patients. Comment Before using the CUSA in surgical procedures, we first experimented with the device on preserved human cadaveric stenotic aortic valves. The device quickly and easily transformed the hardened calcific valves into pliable ones without any apparent weakening of the tissues. The decision was then made to apply this technology not as an alternative for, as has been reported by others [l-5, but rather as an adjunct to replacement procedures to soften the surrounding tissues to facilitate. We believe that the patients undergoing CUSA-assisted at our institutions represent a fair cross section of the Table. Preoperative Hemodynamic Data Variable Mean Value Left ventricular ejection fraction 0.5 f 0. Left ventricular end-diastolic pressure (mm Hg) f 9 Pulmonary artery systolic pressure (mm Hg) 39 Pulmonary artery diastolic pressure (mm Hg) f 9 Cardiac output (L/min) 4.6 f.3 Aortic valve gradient (mm Hg) Mean 6? Peak 90 Aortic valve area (cm )

6 ~~ 64 SHEI'PARD ET AL Ann Thorac Surg 99;5:59-6 Table 3. Postoperative Complications by Patient Patient. Complication Total Ventricular arrhythmia CVA Conduction defect Peptic ulcer Perioperative MI Reoperation for bleeding Pneumothorax Pneumonia Renal failure Pancreatitis Prolonged ventilator weaning NO 6 3 CVA = cerebrovascular accident; MI = myocardial infaction population undergoing currently in the United States. The average age of our patients at the time of operation was years. The hemodynamic variables were consistent with severe aortic stenosis (see Tables, ). Use of the CUSA was not limited to simple s, but included s with coronary artery bypass grafting, repeat s, with mitral valve commissurotomy, with mitral valve replacement, with mitral valve replacement and tricuspid valve annuloplasty, and with repair of aortic dissection. It has been reported [7] that with concomitant coronary artery bypass grafting accounts for % to % of s performed in the United States. This is consistent with our experience, which reveals a 3% association. The general health of our population was what would be expected of sexagenarians and septuagenarians, as they had an average of two secondary diagnoses per patient (see Table ). The four cardiothoracic surgeons among us who used the CUSA in this study find that it greatly facilitates the seating and suturing of the replacement valves. In addition, we believe that use of the CUSA allows placement of the largest possible valve in each patient. The mean aortic cross-clamp time for single is slightly long at 88 * minutes compared with a mean cross-clamp time of 74 * 9 minutes in consecutive single s for aortic stenosis performed by us between 985 and 987, ie, before routine use of the CUSA. There appears to be a learning curve associated with use of the device, as the mean cross-clamp time was f minutes for the patients in the second half of our study. This was not significantly different from the mean of the procedures without CUSA of 74 f 9 minutes (0. < p < 0.3, standard unpaired t test). It should also be noted that use of the CUSA was chosen for the more difficult valves with calcium deposits. This selected for patients who would have had longer cross-clamp times even with standard because of the more difficult debridement. Although the superiority of any technique is subjective by nature, use of the CUSA has become the preferred method for of heavily calcified aortic valves at both of our institutions. Of concern, of course, is what effect the debridement has on the aortic tissue. Scott and associates [] were able to perform histological evaluation of a valve that was ultrasonically debrided in vivo and excised 6 months later. The evaluation revealed an inflammatory response with deposition of collagenous tissue over the residual calcific deposits and reendothelialization of the surface. The fibrosa remained intact. Although the anatomy of the aortic annulus is different, this histological evidence indicates that the procedure removes calcium deposits without extensive damage to softer tissues and that this is followed by an inflammatory repair process. Recent studies [4, 5 with longer follow-up have revealed that aortic insufficiency developed in many patients who underwent CUSA debridement of the aortic valve without replacement. The development of aortic insufficiency was due to fibrosis and retraction of the valves centrally with loss of coaptation [4], which is thought to be a sequela of the inflammatory process affecting the thin valve cusps. As a consequence, use of the CUSA has generally been abandoned as a technique for debriding aortic valves [4, 5, 8. We do not expect this inflammatory repair response to be a problem in the aortic annulus, and it may actually stimulate the healing of the sewing ring. Continued follow-up is warranted, however. Follow-up of our patients has included echocardiographic as well as clinical evaluation. Our follow-up averages f 9 months with a range of to 3 months. The mean follow-up for patients undergoing CUSAassisted before 989 is f 5 months (n = ). Crosby and Muller [9] reported postoperative paraprosthetic regurgitation predisposing to hemolysis or infection in.6% of patients undergoing standard, and Kirklin and Barratt-Boyes [7] showed a 6% rate of clinically recognizable hemolysis as a result of paraprosthetic regur-

7 Ann Thorac Surg 99:5:59-6 SHEPPARD ET AL 65 gitation. ne of our patients, however, have a clinically significant paravalvular leak or show evidence of hemolysis. In addition, a 7% incidence of minor paraprosthetic leakage, ie, not clinically significant, has been reported for standard [7], whereas we have seen no paravalvular leaks in the echocardiograms performed postoperatively. ne of our patients have required reoperation for valvar complications, and no deaths have occurred secondary to valve failure. The mortality rate for our series is comparable with the mortality rate of 4% per year associated with standard techniques of [7]. One concern that we had with the use of this device was the potential for damage to the conduction system. Of the three conduction abnormalities encountered, however, all resolved before the patients were discharged from the hospital. Thus the CUSA, in our experience, does not appear to permanently injure conduction tissue. The cost of using the CUSA at our institutions is only $.00 per patient for the disposable supplies. Most major operating theaters have already purchased this state-of-the-art instrument for use in neurosurgical procedures, and therefore the initial outlay for the equipment is not a monetary concern in such institutions. Based on our experience with the CUSA, we think it greatly facilitates preparation of the aortic annulus for in calcareous degeneration of the valve. Although ultrasonic debridement of the aortic valve as an alternative to is no longer recommended now that longterm follow-up is available [4, 5, 9, we believe that the CUSA has a very definite place in the armamentarium of the aortic valve surgeon. Addendum Since the submission of this report, an additional 9 patients have been added to the series. All survived and none have had a paravalvular leak. Re-replacement of the aortic prosthesis in a 48-year-old woman with a renal transplant was instructive in that the CUSA was very helpful in debriding calcification around the previously placed pledgets as well as removing the calcified pledgets. The underlying anatomy of the aortic root and annulus was preserved for more secure valve placement. Use of the CUSA allowed a 3-mm St. Jude prosthesis to be placed rather than a -mm valve, for which she had been sized before debridement. We thank Debra Moorehead-DeRose for assistance with this project. References. Eguaras MG, Saceda JL, Luque I, Concha M. Mitral and aortic valve decalcification by ultrasonic energy. J Thorac Cardiovasc Surg 988;95:03&.. Scott WJ, Neumann AL, Karp RB. Ultrasonic debridement of the aortic valve with six-month echocardiographic follow-up. Am J Cardiol 989;64: Sternlieb JJ, Basha JW. Ultrasonic restoration of severely calcified aortic valve. Lancet 988;:6. 4. Craver JM. Aortic valve debridement by ultrasonic surgical aspirator: a word of caution. Ann Thorac Surg 990;49:74& McBride LR, Naunheim KS, Fiore AC, et al. Aortic valve decalcification. J Thorac Cardiovasc Surg 990;00: Vander Salm TJ. Mitral annular calcification: a new technique for valve replacement. Ann Thorac Surg 989;48: Kirklin JW, Barratt-Boyes BG. Aortic valve disease. In: Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery. New York: John Wiley, 986: Cosgrove DM, Ratliff NB, Schaff HV, Edwards WD. Aortic valve decalcification: history repeated with a new result [Editorial]. Ann Thorac Surg 990;49: Crosby IK, Muller WH. Acquired disease of the aortic valve. In: Sabiston DC, Spencer FC, eds. Gibbon s surgery of the chest. Philadelphia: W.B. Saunders, 983:9.