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Ann Thorac Surg 1995;60:815-818
© 1995 The Society of Thoracic Surgeons
Division of Cardiothoracic Surgery, Department of Surgery, East Carolina University School of Medicine, Greenville, North Carolina
Abstract
Background. Increasingly complex cardiac procedures demand optimal myocardial protective techniques during the requisite interval of aortic cross-clamping. For complex procedures in which prolonged cross-clamp times are anticipated, we favor combined antegrade and retrograde cold blood cardioplegia. Advantages include rapid arrest, uniform distribution, and an uninterrupted operation.
Methods. We retrospectively evaluated the cases of 194 consecutive patients who underwent complex cardiovascular procedures between January 1988 and October 1994. Procedures performed included valve repair and coronary artery bypass grafting (23.7%), valve replacement and coronary artery bypass grafting (19.1%), complex aortic arch and valve procedures (16.6%), valve repair only (16.5%), reoperative valve (9.8%), and multiple-valve replacements (9.3%). Cardioplegic arrest times averaged 113 +/- 38.5 minutes (range, 52 to 292 minutes).
Results. Postoperative left and right ventricular function was evaluated using transesophageal echocardiography. The echocardiograms revealed a 3.1% incidence of new left ventricular dysfunction and no case of right ventricular dysfunction. Of the patients evaluated, 75.7% required little (<3 µg • kg-1 • min-1 of dopamine hydrochloride) or no inotropic support postoperatively. The 30-day mortality rate was 3.1%, and no death was due to cardiac failure.
Conclusions. We conclude that myocardial protection using a combined antegrade and retrograde cardioplegia technique permits excellent myocardial protection during complex cardiovascular procedures requiring long arrest times.
Advances in nonsurgical treatment of cardiac disease have caused patients to be seen later in the course of the disease process and often with more advanced cardiac dysfunction. The modern cardiac surgeon routinely has patients of advanced age with concurrent valve and coronary artery disease, major left ventricular hypertrophy, and impaired left ventricular function. Moreover, many of them require reoperation. Although these conditions were once relative contraindications to performing bypass procedures, advances in myocardial protective strategies now provide the means necessary to perform complex cardiovascular procedures safely.
Whereas systemic, topical, and infusion hypothermia combined with cardioplegia were the mainstays of myocardial protection in the past, recently a myriad of solutions have been tried in attempts to maintain cardiac electromechanical quiescence during surgical correction. Retrograde coronary sinus infusions of both warm and cold cardioplegic solutions have been shown to be safe and effective. The concept of retrograde delivery of metabolic substrate was described by Pratt in 1898. Lille-hei and colleagues [1] were among the first to use retrograde hypothermic oxygenated blood cardioplegia clinically for myocardial protection during aortic valve operations. A few years later, Shumway [2] raised the question of inadequate right ventricular protection, and retrograde cardioprotection was not adopted clinically at that time. In fact, in 1988, a national survey by Beggerly and associates [3] revealed that less than 1% of surgeons had used retrograde cardioplegia. Recent experimental and clinical studies by Christakis [4], Gundry [5], Buckberg [6], Menasché [7], and their co-workers suggest that retrograde coronary sinus blood cardioplegia may provide an optimal cardioprotective method for valve and coronary surgical procedures.
The anatomic factors influencing cardioplegia delivery include degree of coronary artery disease, existence of coronary collaterals, presence of a patent and noncontrolled internal mammary artery graft (redo procedures), aortic valve incompetence, coronary venous variability, and degree of ventricular hypertrophy. Because complex cardiovascular procedures frequently require prolonged aortic cross-clamp periods, we have adopted the use of combined antegrade and retrograde cardioplegia delivery. Our study hypothesis is that when complex valve operations are done, this combined approach provides optimal myocardial protection during prolonged arrest times.
Material and Methods
Patient Population
To evaluate the efficacy of our approach, we retrospectively evaluated the cases of 194 consecutive patients undergoing complex cardiovascular procedures done between June 1988 and September 1994. Procedures performed included multiple-valve replacements, valve operations plus coronary artery bypass grafting, reoperative valve replacements, and complex mitral valve repairs (Fig 1
). Isolated mitral valve reconstruction was included if a prolonged aortic cross-clamp time was necessary (mean time, 101 +/- 28 minutes). Reoperative procedures were performed in 24 patients (12.4%). Mean patient age was 63.4 +/- 12.91 years (range, 28 to 85 years). As the series was consecutive, all ventricular functional classes were included (Fig 2). Almost one third of patients did not have major coronary artery disease, and the remaining two thirds had variable degrees of coronary artery disease (single-vessel disease, 19.5%; two-vessel disease, 16.1%; three-vessel disease, 33.0%). Of the procedures performed, 67.1% were elective, 24.4% were urgent, and 8.5% were emergent.
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Results
Despite the prolonged cross-clamp times required to perform the procedures, all patients were separated from cardiopulmonary bypass successfully. Normal sinus rhythm returned spontaneously in 93.2%. Although 32.6% of patients required no inotropic support, 43.1% were empirically treated with low-dose dopamine hydrochloride infusions (3 µg • kg-1 • min-1) prior to weaning from cardiopulmonary bypass to prevent cardiac dilatation with subsequent increased myocardial oxygen demand. Generally, this low-dose infusion was continued until the first postoperative morning. Only 16.3% required inotropic support of more than 5 µg • kg-1 • min-1 of dopamine, and only 1 patient (0.5%) required placement of an intra-aortic balloon pump intraoperatively.
Postoperative transesophageal echocardiography was routinely performed and revealed new left ventricular dysfunction in 3.1% of patients and no case of right ventricular dysfunction. The 30-day mortality rate was 3.6%. In every instance, perioperative death was associated with advanced age (mean age, 75 years; range, 71 to 81 years). Although aortic cross-clamp times were not significantly longer for nonsurvivors (122 minutes versus 113 minutes for survivors), 50% demonstrated new left ventricular dysfunction requiring inotropic support. One patient who died had persistent valvular insufficiency. Causes of death included stroke, respiratory failure, renal failure, arrhythmias, and hemorrhage; no death was a direct result of myocardial dysfunction.
Comment
Review of the literature supports combined antegrade and retrograde cardioplegia delivery. Galloway and colleagues [9] reported a series of 513 patients of similar complexity to ours in which only antegrade cold cardioplegia was used. The overall mortality rate was 12.5%; if concomitant coronary artery bypass grafting was performed, the mortality rate was 15.2%. Presumably, the high mortality rate demonstrates inferior myocardial protection achieved with only antegrade cardioplegia in this subset of complex patients. Recent clinical reports by Loop [10]. Menasche [7], Buckberg [6], and their associates employing a combined antegrade and retrograde approach demonstrated greatly reduced mortality rates of 2.8% to 6.2% (Table 1).
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. Antegrade cardioplegia delivered by way of the aortic root or coronary ostia is a relatively facile technique that permits rapid administration of cardioplegic solutions and produces rapid arrest. However, this technique is frequently associated with variable distribution, particularly in the presence of severe coronary artery occlusive disease [12]. Furthermore, incomplete distribution can occur as a result of aortic insufficiency, as 42% of patients undergoing coronary artery bypass grafters have preexisting or transient aortic insufficiency [13]. Finally, antegrade cardioplegia is frequently associated with coronary embolism of atherosclerotic debris in reoperative coronary procedures [5].
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Because each approach is associated with specific merits and shortcomings, we have adopted a physiologically tailored approach that applies the benefit of each technique to the individual patient. Typically, antegrade cardioplegia alone is sufficient in the patient with good left ventricular function undergoing uncomplicated coronary revascularization. For patients having complex operations (valve repair, coronary artery bypass grafting and a valve operation, multiple-valve procedures, aortic reconstruction) or those with severely impaired ventricular function, we favor an approach that combines the salutary effects of antegrade cardioplegic arrest and retrograde maintenance of a quiescent heart. Finally, we use retrograde cardioplegia alone in reoperative coronary procedures to minimize the potential of microembolism or macroembolism.
Recognizing that this is a retrospective series, we believe it demonstrates that antegrade cold blood cardioplegic arrest with intermittent to nearly continuous coronary sinus maintenance provides superb myocardial protection during requisite and generally long arrest times while facilitating the operative aspects by minimizing protective manipulation. This technique is not difficult technically and is associated with a low incidence of complications.
Footnotes
Presented at the International Symposium on Myocardial Protection From Surgical Ischemic-Reperfusion Injury, Asheville, NC, Sep 25--28, 1994.
Address reprint requests to Dr Chitwood, Division of Cardiothoracic Surgery, East Carolina University School of Medicine, Greenville, NC 27858.
References
This article has been cited by other articles:
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  E. Bezon, J. N. Choplain, A. A. Aziz Khalifa, H. Numa, N. Salley, and J. A. Barra Continuous retrograde blood cardioplegia ensures prolonged aortic cross-clamping time without increasing the operative risk Interactive CardioVascular and Thoracic Surgery, August 1, 2006; 5(4): 403 - 407. [Abstract] [Full Text] [PDF]
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 W. J. Flameng, P. Herijgers, S. Dewilde, and E. Lesaffre Continuous retrograde blood cardioplegia is associated with lower hospital mortality after heart valve surgery J. Thorac. Cardiovasc. Surg., January 1, 2003; 125(1): 121 - 125. [Abstract] [Full Text] [PDF]
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 F. Dagenais, L. C. Pelletier, and M. Carrier Antegrade/retrograde cardioplegia for valve replacement: a prospective study Ann. Thorac. Surg., November 1, 1999; 68(5): 1681 - 1685. [Abstract] [Full Text] [PDF]
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