Susan Armstrong
University of Toronto
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The Annals of Thoracic Surgery | 1993
Tirone E. David; Susan Armstrong; Zhao Sun; Loretta Daniel
From June 1981 to August 1992, 184 patients with mitral regurgitation due to degenerative disease underwent mitral valve repair. The mean age was 57 years, and 74% were men. One-third of the patients were in atrial fibrillation, and 71% were in New York Heart Association classes III and IV. The mitral regurgitation was due to prolapse of the posterior leaflet in 97 patients (53%), prolapse of the anterior leaflet in 42 (23%), and prolapse of both leaflets in 45 (24%). The degree of myxomatous changes was assessed intraoperatively as mild in 125 patients (68%), moderate in 27 (15%), and severe in 32 (17%). Mitral valve repair was accomplished largely by techniques described by Carpentier. Ring annuloplasty was performed in 160 patients (66 with Carpentier ring and 94 with Duran ring). There was one operative death, and 5 patients experienced life-threatening complications. Patients were followed up from 5 to 132 months (mean, 41 months). The actuarial survival at 8 years was 88% +/- 4%. The freedom from stroke at 8 years was 94% +/- 2%, and the freedom from transient ischemic attacks was 86% +/- 6%. Age greater than 60 years was the only factor associated with higher risk of thromboembolic complications by logistic regression analysis. The actuarial freedom from reoperation at 8 years was 95% +/- 2%. Advanced myxomatous changes in the leaflets of the mitral valve was the only significant factor associated with a higher risk of reoperation. Most patients were in New York Heart Association class I at the last follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
The Annals of Thoracic Surgery | 1996
Yves d'Udekem; Tirone E. David; Christopher M. Feindel; Susan Armstrong; Zhao Sun
BACKGROUNDnOperation for infective endocarditis with paravalvular abscess is reportedly associated with high mortality and morbidity rates. In an attempt to improve surgical outcome, an approach of radical resection of the abscess and inflamed tissues and reconstruction of the heart with either fresh or glutaraldehyde-fixed bovine pericardium was adopted by two surgeons at our institution.nnnMETHODSnFrom 1979 to 1995, 70 consecutive patients with active infective endocarditis and paravalvular abscess underwent operation. Their mean age was 49 years (range, 16 to 75 years), and 50 patients (71%) were men. Thirty-four patients had native and 36 had prosthetic valve endocarditis (8 had had composite replacement of the aortic valve and ascending aorta). Most patients (78%) were in New York Heart Association functional class IV. The principal indication for operation was cardiogenic or septic shock in 11 patients, or one or more of the following: persistent sepsis despite adequate antibiotic therapy in 36, congestive heart failure in 31, and recurrent emboli in 16. Staphylococci were responsible for the infection in 37 patients (53%). The abscess was in the mitral annulus in 11 patients, in the aortic root in 44, and in the aortic root and at least one other annulus in 15. After wide resection of the abscess, we reconstructed the heart and annuli with autologous or bovine pericardium. Mechanical heart valves were implanted in 36 patients, bioprostheses in 30, and aortic homografts in 2; valve repair was possible in 2. Sixteen patients required composite replacement of the ascending aorta and aortic valve.nnnRESULTSnThere were 9 operative deaths (13%). Infections caused by staphylococci and infections in multiple annuli were associated with increased operative mortality rates. Only 1 patient had persistent infection and required reoperation. The mean follow-up was 56 +/- 40 months. There were 12 late deaths, mostly cardiac. The actuarial survival including operative deaths was 64% +/- 8% at 8 years. In 8 patients, recurrent infective endocarditis developed 10 to 102 months after operation. The freedom from recurrent endocarditis was 76% +/- 10% at 8 years.nnnCONCLUSIONSnThis experience indicates that radical resection of the abscess and reconstruction of the heart with pericardium yield an excellent chance of eradicating the infection in patients with infective endocarditis and paravalvular abscess. The type of valve implanted may not be as important as radical resection of the abscess. These patients appear to have a greater than average risk of recurrent endocarditis.
The Annals of Thoracic Surgery | 1999
Tirone E. David; Susan Armstrong; Joan Ivanov; Gary Webb
BACKGROUNDnAortic valve sparing operations in patients with ascending aorta and/or aortic root aneurysms have been performed for a decade in our institution. Initially only patients with normal aortic valve leaflets had these operations, but more recently we utilized them in patients with prolapse of a single leaflet and in those with a bicuspid aortic valve. This article is an update on the clinical results of these operations.nnnMETHODSnFrom May 1988 to December 1997, 126 patients with ascending aorta and/or aortic root aneurysms and aortic insufficiency underwent replacement of the ascending aorta with reconstruction of the aortic root and preservation of the native aortic valve. There were 85 men and 41 women, with a mean age of 54 years (range, 14 to 84). Thirty-two patients had the Marfan syndrome; 17 patients had acute and 10 had chronic type A aortic dissection; 23 had a transverse arch aneurysm; 26 had coronary artery disease, and 8 had mitral regurgitation. The aortic valve sparing operation consisted of simple adjustment of the sinotubular junction in 33 patients, adjustment of the sinotubular junction and replacement of one or more aortic sinuses in 60, and reimplantation of the aortic valve in a tubular Dacron (C.R. Bard, Haverhill, PA) graft in 33. Fifteen patients also had repair of aortic leaflet prolapse. Only 4 patients had a bicuspid aortic valve.nnnRESULTSnThere were 3 operative deaths due to cardiac failure. Patients were followed from 2 to 117 months, with a mean of 31. There were 11 late deaths: 7 cardiovascular and 4 from unrelated causes. The actuarial survival was 72 +/- 8% at 7 years. Two patients required aortic valve replacement; the freedom from aortic valve replacement was 97 +/- 2% at 7 years. Doppler echocardiography revealed absent, trivial or mild aortic insufficiency in most patients; only 9 patients had moderate aortic insufficiency.nnnCONCLUSIONSnAortic valve sparing operations are feasible in most patients with ascending aorta and/or aortic root aneurysms who have normal or near normal aortic leaflets. The functional results of the repaired aortic valve are excellent, and the repair appears to be durable.
The Journal of Thoracic and Cardiovascular Surgery | 2003
Christopher M. Feindel; Zafar Tufail; Tirone E. David; Joan Ivanov; Susan Armstrong
OBJECTIVESnThe objective of this work was to examine the clinical outcomes of mitral valve surgery in patients with extensive mitral annular calcification.nnnMETHODSnMitral valve surgery was performed in 54 patients (28 men and 26 women, mean age 63 +/- 14 years) with mitral regurgitation and extensive mitral annular calcification. Most patients (78%) were in New York Heart Association classes III and IV, 14 had coronary artery disease, and 9 had prior mitral valve replacement in which the calcium bar was not removed. The calcium bar was excised and a new mitral annulus was created by suturing a strip of pericardium onto the endocardium of the left ventricle from lateral to medial fibrous trigones and to the endocardium of the left atrium. The mitral valve was repaired in 12 patients and replaced in 42. In 23 patients the intervalvular fibrous body was reconstructed and the aortic valve was also replaced. Mean follow-up was 4.1 +/- 3.7 years and was complete.nnnRESULTSnThere were 5 operative deaths and 11 late deaths. Five-year survival was 73 +/- 7%. Four patients needed reoperation and each survived. Freedom from reoperation at 5 years was 89 +/- 6%. Three patients had a stroke and 4 had anticoagulation-related hemorrhage, one of which was fatal. Five-year freedom from valve-related mortality or morbidity was 75 +/- 8%. Most survivors were in New York Heart Association functional classes II and III.nnnCONCLUSIONSnResection of the calcium bar and creation of a new annulus with pericardium provided good clinical results in patients with extensive calcification of the mitral valve.
The Journal of Thoracic and Cardiovascular Surgery | 2013
Tirone E. David; Susan Armstrong; Cedric Manlhiot; Brian W. McCrindle; Christopher M. Feindel
OBJECTIVESnAortic valve sparing is frequently performed to treat patients with aortic root aneurysm, but there is an inadequate amount of information regarding its long-term durability. This study examines the long-term results of reimplantation of the aortic valve in patients with aortic root aneurysms.nnnMETHODSnFrom August 1989 to December 2010, 296 consecutive patients had reimplantation of the aortic valve into a tubular Dacron graft. Their mean age was 45 years (range, 11-79 years), and 78% were men. Of the patients, 36% had Marfan syndrome and 11% had bicuspid aortic valve. Patients were followed prospectively with periodic images of the aortic root and remaining aorta. The mean follow-up was 6.9 ± 4.5 years. There were 21 patients at risk at 15 years.nnnRESULTSnThere were 4 operative and 18 late deaths. The survival at 5, 10, and 15 years was 95.1% ± 3.5%, 93.1% ± 4.4%, and 76.5% ± 18%, respectively. Only 3 patients required reoperation on the aortic valve; all 3 patients had the Bentall procedure. Freedom from reoperation at 5, 10, and 15 years was 99.7% ± 2.0%, 97.8% ± 5.3%, and 97.8% ± 5.3%, respectively. During follow-up, moderate aortic insufficiency developed in 9 patients, and severe aortic insufficiency developed in 2 patients. Freedom from moderate or severe aortic insufficiency at 5, 10, and 15 years was 98.3% ± 3.5%, 92.9% ± 6.5%, and 89.4% ± 12%, respectively.nnnCONCLUSIONSnThe function of the aortic valve implanted inside a tubular Dacron graft remains normal at 15 years in most patients after this type of aortic valve-sparing operation.
The Annals of Thoracic Surgery | 1998
Tirone E. David; Susan Armstrong; Zhao Sun
BACKGROUNDnThe Hancock II bioprosthesis has been used for heart valve replacement since 1982 in our institution. We previously reported its clinical performance at 8 years and at 10 years. This is a progress report on its performance at 12 years.nnnMETHODSnFrom 1982 to 1994 the Hancock II bioprosthesis was used for aortic valve replacement (AVR) in 723 patients and for mitral valve replacement (MVR) in 328 patients. The mean age of the patients was 65 years for both groups. Coronary artery disease was present in 42% of patients who had AVR and 45% of patients who had MVR. Patients have been followed up prospectively at annual intervals; the mean follow-up was 68+/-40 months for AVR and 66+/-43 months for MVR; it was 99% complete.nnnRESULTSnThere were 36 (5%) operative and 159 late deaths in the AVR group, and 26 (8%) operative and 92 late deaths in the MVR. The actuarial survival at 12 years was 54%+/-4% for AVR and 42%+/-5% for MVR. Age greater than 65 years and coronary artery disease had a profound effect on late survival. At 12 years the freedom from thromboembolism was 86%+/-2% for AVR and 90% +/-2% for MVR; from endocarditis, 95%+/-1% for both groups; from primary tissue failure, 94%+/-2% for AVR and 82%+/-5% for MVR; and from valve reoperation, 89% +/-3% for AVR and 78%+/-5% for MVR. There was no primary tissue failure at 12 years in patients older than 65 years who had AVR.nnnCONCLUSIONSnThe clinical performance of the Hancock II has been very satisfactory and this bioprosthesis appears to be more durable than its predecessors.
The Journal of Thoracic and Cardiovascular Surgery | 2010
Tirone E. David; Anna Woo; Susan Armstrong; Manjula Maganti
OBJECTIVEnWe sought to identify suitable patients for the Ross operation.nnnMETHODSnA cohort of 212 patients (mean age, 34 + or - 9 years; 66% men; 82% with congenital aortic valve disease) underwent the Ross operation and was prospectively followed with clinical evaluations and echocardiographic analysis for 3.1 to 18 years (mean, 10.1 + or - 4.2 years). In addition to longitudinal outcomes determined by means of Kaplan-Meier analysis, Cox regression analysis was used to identify predictors of valve failure.nnnRESULTSnThere were 1 operative and 4 late deaths, none of which were valve related. Survival at 15 years was 96.6% + or - 1.5% and similar to that seen in the general population matched for age and sex. There were 20 reoperations: 13 in the pulmonary autograft, 3 in the pulmonary homograft, and 4 others. Freedom from reoperation in the pulmonary autograft at 15 years was 92.1% + or - 2.3%. Aortic insufficiency was the only independent predictor of reoperation. Freedom from moderate or severe aortic insufficiency at 15 years was 89.7%, and greater than mild aortic insufficiency was 63.2%. Male sex, aortic/pulmonary annular mismatch, aortic annulus of 27 mm or larger, and preoperative aortic insufficiency were associated with higher risk of late aortic insufficiency by means of log-rank analysis. Cox regression analysis identified male sex as the only independent predictor of postoperative aortic insufficiency. Freedom from moderate or severe pulmonary insufficiency, peak gradient of 40 mm Hg or greater, or both at 15 years was 70.8% + or - 6.8%, and event-free survival was 81% + or - 3.7%.nnnCONCLUSIONSnThe Ross operation provided suboptimal results in male patients with aortic insufficiency. The best outcomes were in female patients, those with aortic stenosis, and those with an aortic annulus of less than 27 mm in diameter.
Seminars in Thoracic and Cardiovascular Surgery | 1998
Tirone E. David; Susan Armstrong
Repair of postinfarction ventricular septal defect (VSD) by infarct exclusion has been used for a decade in our unit. It involves securing a glutaraldehyde-preserved bovine pericardial patch to the endocardium of the left ventricle all around the necrotic myocardium to exclude the VSD and the infarct from the left ventricular cavity. Fifty-two patients with postinfarction VSD underwent this type of repair from 1987 to 1996. Thirty-four patients were in shock when undergoing operation; 26 had anterior VSD and 26 had posterior. Ten patients died perioperatively, for surgical mortality of 19%. Three patients developed recurrent VSD; one died and two survived. Preoperative cardiogenic shock and age older than 70 years were associated with an increased operative mortality. Operative survivors were followed up from 6 to 135 months, mean of 65 months. The actuarial survival at 8 years was 59% +/- 6%. Repair of postinfarction VSD by infarct exclusion is a relatively simple operative procedure and seems to have improved the results of surgery in patients with posterior VSD.
The Journal of Thoracic and Cardiovascular Surgery | 1999
Gideon Cohen; Tirone E. David; Joan Ivanov; Susan Armstrong; Christopher M. Feindel
OBJECTIVESnThis study was designed to determine the effects of age, coronary artery disease and other cardiac comorbidities on late outcome following bioprosthetic aortic valve replacement.nnnMETHODSnData were prospectively collected on 670 patients undergoing aortic valve replacement with the Hancock II bioprosthesis (Medtronic, Inc, Minneapolis, Minn) between 1982 and 1994. Mean patient age was 65 +/- 12 years (median, 68 years; range, 18-86 years). Follow-up was 99.7% complete at 69 +/- 40 months (median, 66 months; range, 0. 1-168 months). Survival and freedom from reoperation were evaluated univariately by Kaplan-Meier analysis and multivariably by Cox regression.nnnRESULTSnAfter adjustment for gender, Cox regression analysis revealed that age of 65 years or older, left ventricular dysfunction, the presence of coronary artery disease, and advanced New York Heart Association functional classification were associated with a higher risk of late death. At 12 years, survival was significantly different by Kaplan-Meier analysis for both age younger than 65 years (71% +/- 4%) versus age 65 years or older (36% +/- 7%; P <.0001), left ventricular function grades 3 and 4 (26% +/- 13%) versus grades 1 and 2 (59% +/- 4%; P <.0001), no coronary artery disease (65% +/- 4%) versus coronary artery disease (35% +/- 8%; P <.0001), and functional class IV (33% +/- 9%) versus classes I to III (62% +/- 4%; P <.0001). Only 9 patients experienced primary tissue failure, all of whom were younger than 65 years of age. At 12 years, the freedom from primary tissue failure was 84% +/- 4% for those patients younger than 65 years of age, and 100% for those 65 years of age or older (P =.006).nnnCONCLUSIONSnLong-term survival after aortic valve replacement is highly dependent on age, coronary artery disease, functional class, and left ventricular function, although bioprosthetic durability is dependent almost solely on age. Due to increased valve durability in patients who are 65 years of age or older, the Hancock II bioprosthesis may be an ideal aortic valve substitute in this age group. In patients who are younger than 65 years of age with advanced functional class, impaired left ventricular function, and coronary artery disease, this valve may also be used with a low probability of primary tissue failure. Patients without additional cardiac comorbidity may outlive their bioprosthetic valve, leading to reoperation.
The Annals of Thoracic Surgery | 1992
Tirone E. David; Susan Armstrong; Zhao Sun
The Hancock II bioprosthesis was used for heart valve replacement in 614 patients from 1982 to 1990. Aortic valve replacement (AVR) was performed in 376 patients, mitral valve replacement (MVR) in 195, and aortic and mitral valve replacement (DVR) in 43. The mean age was 62.7 years, and 78% of all patients were in New York Heart Association functional class III or IV before operation. Coronary artery bypass graft was necessary in 232 patients and replacement of ascending aorta in 55. There were 31 operative deaths (AVR, 4%; MVR, 6%; DVR, 9%). Follow-up was complete in 98.5% of the patients and extended from 12 to 103 months, with a mean of 49 months. At the last follow-up, 85% of the patients were in New York Heart Association class I or II. The actuarial survival at 8 years was 79% +/- 3% for AVR, 68% +/- 4% for MVR, and 65% +/- 10% for DVR. The freedom from stroke at 8 years was 93% +/- 2% for AVR, 83% +/- 5% for MVR, and 90% +/- 5% for DVR. At the end of 8 years 96% +/- 1% of all patients were free from endocarditis, 92% +/- 1% were free from primary tissue failure, and 89% +/- 3% were free from reoperation. The actuarial freedom from valve-related death at 8 years was 98% +/- 1% for AVR, 86% +/- 5% for MVR, and 91% +/- 6% for DVR. Hemodynamic assessment was obtained by Doppler echocardiography in all operative survivors and demonstrated satisfactorily effective valve orifices and transvalvular gradients. The clinical results obtained with the Hancock II bioprosthesis have been gratifying, particularly in the aortic position. This bioprosthesis is our biological valve of choice.