Invited Commentary

Abstract

This report by Perrotta and associates [1Perrotta S. Jeppsson A. Fröjd V. Svensson G. Surgical treatment of aortic prosthetic valve endocarditis: a 20-year single-center experience.Ann Thorac Surg. 2016; 101: 1426-1433Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] from Gothenburg, Sweden, describes their institutional experience with the surgical management of prosthetic valve endocarditis over a 20-year period. Overall mortality was admirably low (10%), and the risk of death early after operation decreased from 22% to 3.6% during the most recent decade. The 5-year survival also improved during the past 10 years. The procedures were tailored to the operative findings, mainly dictated by the degree of annular tissue destruction; 32% of patients had isolated valve replacement, and 68% of patients underwent root replacements, most with an aortic valve homograft.So, what can the reader take away from this experience that may help in patient treatment? The analysis of available data demonstrated that in addition to year of operation, elevated preoperative serum creatinine and systemic hypertension were the only independent predictors of early mortality. A history of systemic hypertension is a common risk factor for early and late mortality for many cardiac procedures; and its sequelae cannot be modified immediately preoperatively. Elevated serum creatinine probably reflects poor perfusion, antibiotic nephrotoxicity, and, to some degree, delayed operation. But beyond these factors it is difficult to account for the improved results over time aside from general refinements in operative and perioperative care.One aspect of this series that does stand out is the relatively frequent use of aortic valve allografts (64% of patients). Allografts are particularly useful in the management of aortic valve endocarditis when there is annular abscess formation because the mitral curtain and associated myocardium of the allograft can be used to reconstruct damaged tissue [2Kirklin J.K. Pacifico A.D. Kirklin J.W. Surgical treatment of prosthetic valve endocarditis with homograft aortic valve replacement.J Card Surg. 1989; 4: 340-347Crossref PubMed Scopus (17) Google Scholar, 3McGiffin D.C. Kirklin J.K. The impact of aortic valve homografts on the treatment of aortic prosthetic valve endocarditis.Semin Thorac Cardiovasc Surg. 1995; 7: 25-31PubMed Google Scholar, 4Lopes S. Calvinho P. de Oliveira F. et al.Allograft aortic root replacement in complex prosthetic endocarditis.Eur J Cardiothorac Surg. 2007; 32 (discussion 131–2): 126-130Crossref PubMed Scopus (39) Google Scholar, 5Dearani J.A. Orszulak T.A. Schaff H.V. et al.Results of allograft aortic valve replacement for complex endocarditis.J Thorac Cardiovasc Surg. 1997; 113: 285-291Abstract Full Text Full Text PDF PubMed Scopus (70) Google Scholar]. Also, many surgeons believe that allografts have a low risk of reinfection. Indeed, in this series the 3 patients who experienced recurrent infection after initial valve re-replacement (2 with biologic prostheses and 1 with a mechanical prosthesis) underwent reoperation with allograft re-replacement. But allografts are not perfect substitutes. In this series, at the time of diagnosis of endocarditis, 5 patients (6%) had an aortic allograft in place. Furthermore, there was no significant difference in early or late survival between patients who had allografts and those who had stented bioprostheses or mechanical valves. And this finding is consistent with those of a recent multicenter study by Kim and colleagues (Kim JB, Ejiofor JI, Yammine M, et al. Are homografts superior to prosthetic valves in the setting of infective endocarditis? Presented at the Western Thoracic Surgical Association annual meeting, Whistler, British Columbia, June 27, 2015) that showed no difference in survival or recurrent infection among patients with active aortic valve endocarditis undergoing operation with aortic valve allograft, a stented heterograft, or a mechanical prosthesis.One finding in the current report that deserves further study is the 12% incidence of perioperative stroke. Each of the 11 patients with perioperative stroke had brain infarctions documented by computed tomographic scans, and these were almost certainly embolic in origin. Some of them might have been “silent” infarctions present preoperatively and manifested after operation [6Misfeld M. Girrbach F. Etz C.D. et al.Surgery for infective endocarditis complicated by cerebral embolism: a consecutive series of 375 patients.J Thorac Cardiovasc Surg. 2014; 147: 1837-1844Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar], but the finding emphasizes the importance of special care in cannulation, debridement, and valve implantation in patients with prosthetic valve endocarditis.Although not specifically documented in this study, the interval between identification of prosthetic valve infection and surgical treatment may have had some influence on operative mortality and long-term outcome. It is possible that the better results in the current era reported by Perrotta and associates relate, in part, to earlier identification of infection and timely surgical intervention. There is a general trend toward earlier operation in patients with native valve endocarditis because of lower risks of embolism, death, and reinfection [7Kim D.H. Kang D.H. Lee M.Z. et al.Impact of early surgery on embolic events in patients with infective endocarditis.Circulation. 2010; 122: S17-22Crossref PubMed Scopus (77) Google Scholar, 8Kang D.H. Kim Y.J. Kim S.H. et al.Early surgery versus conventional treatment for infective endocarditis.N Engl J Med. 2012; 366: 2466-2473Crossref PubMed Scopus (548) Google Scholar, 9Kang D.H. Timing of surgery in infective endocarditis.Heart. 2015; http://dx.doi.org/10.1136/heartjnl-2015-307878Google Scholar], and the same is likely true for patients with prosthetic valve endocarditis. Indeed, evidence is accumulating that early operation even in the face of neurologic events is associated with good outcome and a relatively low risk of subsequent neurologic deterioration [10Yoshioka D. Sakaguchi T. Yamauchi T. et al.Impact of early surgical treatment on postoperative neurologic outcome for active infective endocarditis complicated by cerebral infarction.Ann Thorac Surg. 2012; 94 (discussion 496): 489-495Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar, 11Yoshioka D. Toda K. Sakaguchi T. et al.Valve surgery in active endocarditis patients complicated by intracranial haemorrhage: the influence of the timing of surgery on neurological outcomes.Eur J Cardiothorac Surg. 2014; 45: 1082-1088Crossref PubMed Scopus (43) Google Scholar, 12Sorabella R.A. Han S.M. Grbic M. et al.Early operation for endocarditis complicated by preoperative cerebral emboli is not associated with worsened outcomes.Ann Thorac Surg. 2015; 100: 501-508Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar]. This report by Perrotta and associates [1Perrotta S. Jeppsson A. Fröjd V. Svensson G. Surgical treatment of aortic prosthetic valve endocarditis: a 20-year single-center experience.Ann Thorac Surg. 2016; 101: 1426-1433Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] from Gothenburg, Sweden, describes their institutional experience with the surgical management of prosthetic valve endocarditis over a 20-year period. Overall mortality was admirably low (10%), and the risk of death early after operation decreased from 22% to 3.6% during the most recent decade. The 5-year survival also improved during the past 10 years. The procedures were tailored to the operative findings, mainly dictated by the degree of annular tissue destruction; 32% of patients had isolated valve replacement, and 68% of patients underwent root replacements, most with an aortic valve homograft. So, what can the reader take away from this experience that may help in patient treatment? The analysis of available data demonstrated that in addition to year of operation, elevated preoperative serum creatinine and systemic hypertension were the only independent predictors of early mortality. A history of systemic hypertension is a common risk factor for early and late mortality for many cardiac procedures; and its sequelae cannot be modified immediately preoperatively. Elevated serum creatinine probably reflects poor perfusion, antibiotic nephrotoxicity, and, to some degree, delayed operation. But beyond these factors it is difficult to account for the improved results over time aside from general refinements in operative and perioperative care. One aspect of this series that does stand out is the relatively frequent use of aortic valve allografts (64% of patients). Allografts are particularly useful in the management of aortic valve endocarditis when there is annular abscess formation because the mitral curtain and associated myocardium of the allograft can be used to reconstruct damaged tissue [2Kirklin J.K. Pacifico A.D. Kirklin J.W. Surgical treatment of prosthetic valve endocarditis with homograft aortic valve replacement.J Card Surg. 1989; 4: 340-347Crossref PubMed Scopus (17) Google Scholar, 3McGiffin D.C. Kirklin J.K. The impact of aortic valve homografts on the treatment of aortic prosthetic valve endocarditis.Semin Thorac Cardiovasc Surg. 1995; 7: 25-31PubMed Google Scholar, 4Lopes S. Calvinho P. de Oliveira F. et al.Allograft aortic root replacement in complex prosthetic endocarditis.Eur J Cardiothorac Surg. 2007; 32 (discussion 131–2): 126-130Crossref PubMed Scopus (39) Google Scholar, 5Dearani J.A. Orszulak T.A. Schaff H.V. et al.Results of allograft aortic valve replacement for complex endocarditis.J Thorac Cardiovasc Surg. 1997; 113: 285-291Abstract Full Text Full Text PDF PubMed Scopus (70) Google Scholar]. Also, many surgeons believe that allografts have a low risk of reinfection. Indeed, in this series the 3 patients who experienced recurrent infection after initial valve re-replacement (2 with biologic prostheses and 1 with a mechanical prosthesis) underwent reoperation with allograft re-replacement. But allografts are not perfect substitutes. In this series, at the time of diagnosis of endocarditis, 5 patients (6%) had an aortic allograft in place. Furthermore, there was no significant difference in early or late survival between patients who had allografts and those who had stented bioprostheses or mechanical valves. And this finding is consistent with those of a recent multicenter study by Kim and colleagues (Kim JB, Ejiofor JI, Yammine M, et al. Are homografts superior to prosthetic valves in the setting of infective endocarditis? Presented at the Western Thoracic Surgical Association annual meeting, Whistler, British Columbia, June 27, 2015) that showed no difference in survival or recurrent infection among patients with active aortic valve endocarditis undergoing operation with aortic valve allograft, a stented heterograft, or a mechanical prosthesis. One finding in the current report that deserves further study is the 12% incidence of perioperative stroke. Each of the 11 patients with perioperative stroke had brain infarctions documented by computed tomographic scans, and these were almost certainly embolic in origin. Some of them might have been “silent” infarctions present preoperatively and manifested after operation [6Misfeld M. Girrbach F. Etz C.D. et al.Surgery for infective endocarditis complicated by cerebral embolism: a consecutive series of 375 patients.J Thorac Cardiovasc Surg. 2014; 147: 1837-1844Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar], but the finding emphasizes the importance of special care in cannulation, debridement, and valve implantation in patients with prosthetic valve endocarditis. Although not specifically documented in this study, the interval between identification of prosthetic valve infection and surgical treatment may have had some influence on operative mortality and long-term outcome. It is possible that the better results in the current era reported by Perrotta and associates relate, in part, to earlier identification of infection and timely surgical intervention. There is a general trend toward earlier operation in patients with native valve endocarditis because of lower risks of embolism, death, and reinfection [7Kim D.H. Kang D.H. Lee M.Z. et al.Impact of early surgery on embolic events in patients with infective endocarditis.Circulation. 2010; 122: S17-22Crossref PubMed Scopus (77) Google Scholar, 8Kang D.H. Kim Y.J. Kim S.H. et al.Early surgery versus conventional treatment for infective endocarditis.N Engl J Med. 2012; 366: 2466-2473Crossref PubMed Scopus (548) Google Scholar, 9Kang D.H. Timing of surgery in infective endocarditis.Heart. 2015; http://dx.doi.org/10.1136/heartjnl-2015-307878Google Scholar], and the same is likely true for patients with prosthetic valve endocarditis. Indeed, evidence is accumulating that early operation even in the face of neurologic events is associated with good outcome and a relatively low risk of subsequent neurologic deterioration [10Yoshioka D. Sakaguchi T. Yamauchi T. et al.Impact of early surgical treatment on postoperative neurologic outcome for active infective endocarditis complicated by cerebral infarction.Ann Thorac Surg. 2012; 94 (discussion 496): 489-495Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar, 11Yoshioka D. Toda K. Sakaguchi T. et al.Valve surgery in active endocarditis patients complicated by intracranial haemorrhage: the influence of the timing of surgery on neurological outcomes.Eur J Cardiothorac Surg. 2014; 45: 1082-1088Crossref PubMed Scopus (43) Google Scholar, 12Sorabella R.A. Han S.M. Grbic M. et al.Early operation for endocarditis complicated by preoperative cerebral emboli is not associated with worsened outcomes.Ann Thorac Surg. 2015; 100: 501-508Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar]. Surgical Treatment of Aortic Prosthetic Valve Endocarditis: A 20-Year Single-Center ExperienceThe Annals of Thoracic SurgeryVol. 101Issue 4PreviewDespite progress in diagnostic methods and treatment, aortic prosthetic valve endocarditis (PVE) remains a life-threatening disease. We report the outcome of all operations for aortic PVE performed at our institution over the past 20 years. Full-Text PDF