CORRESPONDENCE

Retrograde Low-Dilution Continuous Normothermic Blood Cardioplegia To the Editor:

Gundry and associates [ l ] recently reported their experience obtained in 100 patients undergoing cardiac operations with retrograde continuous warm blood cardioplegia (CWBC) (4:l dilution). However, retrograde CWBC obtained with addition of potassium, magnesium, and citrate-phosphate-dextrose to the pump perfusate as proposed by Le Houerou and Lessana [2] seems to overcome some drawbacks of their technique, although the evaluation of the perfusion efficacy and the way to face possible complications are still unsettled. On the other hand, an intermittent antegrade technique with 2 minutes of perfusion and 10 to 15 minutes of flow interruption has proved to be safe both in pediatric [3] and adult [4] patients.

Since October 1992 retrograde induction and maintenance of CWBC has been routinely used in our institution. Cardiac stand- still was achieved within 60 to 120 seconds while monitoring the infusion pressure curve [5]; the cannula was carefully reposi- tioned, if necessary. Even later during operation the cannula position and the perfusion flow were occasionally further readapted depending on surgical exposure, particularly during mitral operations and circumflex territory revascularization. Wedging and atrial displacement of the cannula were the most frequent complications. Blind repositioning of the coronary sinus cannula was usually successful. Because we do not accept flow interruption for periods longer than 3 minutes, we routinely performed antegrade and retrograde connection at the beginning of the operation, and the perfusion was immediately switched to the antegrade route as soon as any complication occurred, allowing careful and unhurried efforts to solve the problem. When this could not be achieved, we continued antegrade normothermic cardioplegia to the end of the operation (in about 5% of our patients).

So far, 154 consecutive unselected adult patients with acquired heart disease have undergone retrograde induction and mainte- nance of CWBC. Mean aortic cross-clamping time was 77.2 2 32.5 minutes. Spontaneous sinus rhythm was recovered within a few minutes from aortic declamping in 90% of the patients. Overall 30-day mortality was 3.2%, major inotropic support was needed in 6.5%, and intraaortic balloon pump support in 2.6%. The incidence of perioperative acute myocardial infarction was 4.5%. These data are similar to those obtained with antegrade induction of CWBC and compare favorably with our previous results of intermittent crystalloid cardioplegia.

Retrograde induction and maintenance of CWBC is a simple and adjustable technique in most anatomic and clinical situa- tions, specifically suitable for aortic valve operations and redo revascularization. It allows immediate assessment of the ade- quacy of cardioplegic delivery and uninterrupted surgical proce- dures for periods of aortic cross-clamping up to 4 hours. Inter- mittent antegrade normothermic blood cardioplegia is a quick and efficient alternative when retrograde perfusion fails, elimi- nating the necessity for hypothermic myocardial protection and perfusion.

Tiziano Bianchi, M D

Department of Cardiac Surgery Ospedali Riuniti Largo Barozzi 1 241 00 Bergamo ltaly

0 1993 by The Society of Thoracic Surgeons

References 1.

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Gundry SR, Wang N, Bannon D, et al. Continuous warm blood retrograde cardioplegia: maintenance of myocardial homeostasis and elimination of myocardial ischemia in hu- mans. Ann Thorac Surg 1993;55:35&63. Le Houerou D, Singh AI, Romano M, et al. Minimal hemodi- lution and optimal potassium use during normothermic aero- bic arrest [Letter]. Ann Thorac Surg 1992;54:815-6. Cartier P. Warm blood cardioplegia in congenital heart sur- gery. Acta of the Meeting on Aerobic Cardiac Surgery, Ber- gamo, Italy, 1993:27-8. Calafiore AM, Cappelletti L, Verna AM, et al. Intermittent antegrade warm blood cardioplegia: report of a consecutive series of 173 patients. Acta of the Meeting on Aerobic Cardiac Surgery, Bergamo, Italy, 1993:30-3. Lessana A, Romano M, Sigh AL, et al. Beyond cold cardio- plegia. Ann Thorac Surg 1992:53:666-9.

Reply To the Editor:

We appreciate Dr Bianchi's letter describing his experience of warm continuous retrograde cardioplegia in 154 patients. It is clear from experiences such as his that retrograde induction of cardiac arrest and maintenance of myocardial homeostasis by retrograde cardioplegia alone can be reliably performed in a large number of patients at institutions other than ours. Doctor Bian- chi's point of temporarily using antegrade warm cardioplegia, should the retrograde cannula be displaced, is well taken; we have used just such a technique for the last 3 years. Replacement of the retrograde cannula can then be accomplished in an unhurried fashion, without concern for a warm, ischemic heart. Additionally, we have found it easier to reinsert the retrograde cannula if the perfusionist holds blood so that the right atrium gently distends, thus opening the coronary sinus orifice.

Small refinements in technique and the recognition of variabil- ity in the retrograde flow requirements to ensure myocardial viability are increasing the safety of warm continuous retrograde cardioplegia. Letters such as Dr Bianchi's do much to lessen the fears attendant to any new technique.

Steven R. Gundry, M D

Division of Cardiothoracic Surgery Lorna Linda University Medical Center Rm 2573 11234 Anderson St Loma Linda, C A 92354

Early Use of Internal Thoracic Artery To the Editor:

Credit should undoubtedly be given to Dr Favaloro for being the first surgeon to make possible an operation for bypassing the obstructed coronary artery with venous grafts removed from the patient's legs, as reported in 1967 [l]. Even though this operation could have been done before in a few desperate cases, no communication was made of such cases and therefore credit belongs legitimately to Dr Favaloro.

However, those were not the first bypass operations. The first bypass operation was done in May of 1960 by Dr Robert Goetz, a vascular surgeon at the Bronx Municipal Hospital Center in New York City as reported in the Journal of Thoracic Surgery 121. Different from Dr Favaloro, Dr Goetz used the internal mammary artery for bypassing the obstructed coronary artery. The use of this artery has several advantages and some disadvantages over

Ann Thorac Surg 1993;56:143t?44 0003-4975/93/$6.00