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Biomedical subjects

Gus J Vlahakes

Publications and source records attributed to Gus J Vlahakes.

At least 19 recordsLinked to original sources
PubMed2006

The impact of spontaneous echocardiographic contrast in patients with left atrial enlargement undergoing cardiac valvular surgery.

OBJECTIVE: The aim of this study was to evaluate the impact of either left atrial or aortic spontaneous echocardiographic contrast (SEC), as identified on intraoperative transesophageal echocardiography, on short-term morbidity and mortality in patients with left atrial enlargement undergoing cardiac valvular surgery. DESIGN: Retrospective and observational. SETTING: Single-center, university teaching hospital. PARTICIPANTS: The authors identified 197 patients (105 males and 92 females; mean age, 68 +/- 14 years) with left atrial enlargement who underwent surgical intervention for valvular heart disease from January 1, 2004 to January 1, 2005. MAIN RESULTS: Of the total population, 40 patients (20.3%) showed left atrial SEC, and 10 patients (5.1%) showed aortic SEC. On multivariate analysis, increasing left atrial size and the absence of mitral regurgitation were independent predictors for the presence of left atrial SEC. On multivariate analysis, the presence of atrial fibrillation and a dilated descending aorta were predictive of aortic SEC. Although the identification of left atrial SEC was an echocardiographic marker of an increased risk for thromboembolic events postoperatively, this finding did not hold true for the presence of aortic SEC. CONCLUSIONS: Intraoperative identification of left atrial dilatation or aortic dilatation is predictive of SEC in the left atrium or descending aorta, respectively. The identification of left atrial SEC is an echocardiographic marker of an increased risk for thromboembolic events in this high-risk population.

Academic Medical Centers↗
PubMed2006

Chordal cutting does not adversely affect left ventricle contractile function.

BACKGROUND: Severing a limited number of second-order chordae to the anterior leaflet can improve ischemic mitral regurgitation (MR). Some concerns have been raised regarding possible influence on regional and global left ventricle (LV) function. We evaluated changes in cardiac function in 5 normal sheep with cutting of pre-instrumented chords in the beating heart to maintain constant load. METHODS AND RESULTS: Under cardiopulmonary bypass, wires were placed around the 2 central basal chordae and brought outside the heart, which was restarted. Hemodynamic and imaging data were collected before and after chordal cutting by radiofrequency ablation using those wires. Segmental contractility was assessed invasively using sonomicrometers and noninvasively using Doppler tissue velocity and strain rate (with strain rate viewed as less load-dependent than ejection fraction) at 6 sites: base, mid-ventricle, and apex along the anteroseptal and posterolateral walls. We found no changes from before to after chordal cutting in LV end-diastolic volume (47.2+/-3.3 after cutting versus 48.4+/-4.6 mL before cutting, P=0.66), end-systolic volume (21.5+/-1.2 versus 22.3+/-2.8 mL, P=0.68), ejection fraction (54.2+/-1.8 versus 54.2+/-2.7%, P=0.96), systolic ventricular elastance (7.28+/-1.68 versus 7.66+/-2.11 mm Hg/mL, P=0.64), preload-recruitable stroke work (46.6+/-7.7 versus 50.2+/-10.7 mm Hg, P=0.76), and LVdP/dt (1480+/-238 versus 1392+/-250 mm Hg/s, P=0.45). Doppler tissue velocities and longitudinal strain rates surrounding the papillary muscles were unchanged, as were sonomicrometer longitudinal and mediolateral absolute strains. No wall motion abnormalities were visible around the papillary muscles, and no MR developed. CONCLUSIONS: We find no evidence for acutely decreased global or segmental LV contractility with chordal cutting. This absence of adverse effects is consistent with long-term clinical experience with cutting these chords in valve repair.

Animals↗
PubMed2006

Sustained improvement in left ventricular diastolic function after alcohol septal ablation for hypertrophic obstructive cardiomyopathy.

AIMS: Impaired diastolic function is responsible for many of the clinical features of hypertrophic cardiomyopathy. In patients with hypertrophic obstructive cardiomyopathy (HOCM) whose symptoms are refractory to medical therapy, alcohol septal ablation (ASA) reduces left ventricular (LV) outflow tract gradient, with short-term improvement in LV diastolic function. Little is known about the longer term impact of ASA on diastolic function. METHODS AND RESULTS: We evaluated LV diastolic function at baseline and 1- and 2-year follow-up after successful ASA. In 30 patients (58+/-15 years, 22 men) who underwent successful ASA, New York Heart Association class was lower at 1-year follow-up compared with baseline (3.0+/-0.5 to 1.5+/-0.7; P<0.0001). LV outflow tract gradient (76+/-37 to 19+/-12; P<0.0001), interventricular septal thickness (19+/-2 to 14+/-2; P<0.0001), and left atrial volume (26+/-5 to 20+/-4; P<0.0001) were decreased. Significant improvement in E-wave deceleration time, isovolumic relaxation time, early diastolic mitral lateral annular velocity (E'), mitral inflow propagation velocity (V(p)), ratio of transmitral early LV filling velocity (E) to early diastolic Doppler tissue imaging of the mitral annulus (E/E'), and E/V(p) were observed at 1 year following successful ASA. These changes persisted in the subset cohort (n=21) for whom 2-year data were available. CONCLUSION: Successful ASA for HOCM leads to significant and sustained improvement in echocardiographic measures of diastolic function, which may contribute to improved functional status after successful ASA.

Adult↗
PubMed2006

Time course of pressure gradient response after first alcohol septal ablation for obstructive hypertrophic cardiomyopathy.

Alcohol septal ablation (ASA) causes remodeling of the upper septum and left ventricular outflow tract (LVOT) and reduction in the LVOT gradient. The time course of gradient reduction early after ASA has not been established. This study characterized the time course of gradient response early after ASA. Patients underwent clinical assessment and transthoracic echocardiography at baseline and immediately, 3 days, 3 months, and 1 year after ASA. Forty-seven patients underwent ASA. The baseline LVOT gradient was 98 +/- 48 mm Hg. Three-month echocardiographic success, defined as > or = 50% gradient reduction from baseline, was achieved in 41 procedures (87%); thus, there were 6 failures. On the basis of percentage reduction in LVOT gradient at 3 days, 2 distinct subgroups of the success group were identified. These were monophasic success (> or = 50% gradient reduction at 3 days and 3 months, n = 25) and triphasic success (< 50% gradient reduction at 3 days but > or = 50% gradient reduction at 3 months, n = 16). LVOT gradient in the triphasic success group was similar to that in the failure group at 3 days (81 +/- 28 vs 99 +/- 31 mm Hg, p = NS) but similar to that of the monophasic success group at 3 months (24 +/- 20 vs 12 +/- 16 mm Hg, p = NS) and at 1 year (27 +/- 24 vs 13 +/- 20 mm Hg, p = NS). In conclusion, many patients who undergo ultimately successful ASA demonstrate triphasic LVOT gradient response patterns, with a large gradient 3 days after the procedure.

Analysis of Variance↗
PubMed2005

Long-term survival after surgical revascularization for moderate ischemic mitral regurgitation.

BACKGROUND: We sought to characterize patient survival and degree of late mitral regurgitation (MR) in patients undergoing surgical revascularization with moderate ischemic MR. METHODS: We retrospectively reviewed 251 patients undergoing coronary artery bypass graft (CABG) surgery between 1991 and 2001 with 3+ ischemic MR, including 31 patients who had concomitant mitral annuloplasty. Univariate and multivariable testing was employed. RESULTS: Actuarial 1-, 5-, and 10-year survival was 84.0%, 67.5%, and 37.1% in the overall group of 251 patients. Independent predictors of long-term mortality were age 70 years or more (hazard ratio 2.50 [95% confidence interval 1.82 to 3.44]), prior myocardial infarction (3.99 [2.15 to 7.39]), unstable angina (2.27 [1.69 to 3.04]), chronic renal failure (4.87 [3.13 to 7.58]), atrial fibrillation (2.21 [1.65 to 2.96]), left internal mammary artery to left anterior descending artery graft (0.28 [0.18 to 0.43]), preoperative beta-blocker (0.43 [0.28 to 0.67]), ejection fraction (0.71/10% [0.64 to 0.80]), left atrium size (0.88/mm [0.84 to 0.92]), diffuse wall motion abnormalities (2.83 [1.77 to 4.55]), and mitral leaflet restriction (3.85 [2.46 to 5.99]). The model controlled for the performance of annuloplasty, which did not emerge as an independent predictor. Patients undergoing annuloplasty did have less mean late MR than those having CABG alone (p = 0.005). Overall, 57.8% of patients (63 of 109) with follow-up echocardiograms had improvement in grade of MR compared with baseline. In 54 of 95 patients (56.8%), intraoperative transesophageal echocardiography downgraded the degree of MR compared with the preoperative study. CONCLUSIONS: Patients with moderate ischemic MR undergoing CABG had relatively poor long-term survival, with significant differences when stratified according to preoperative characteristics. Performance of mitral annuloplasty reduced the degree of regurgitation but was not a predictor of long-term survival. Intraoperative transesophageal echocardiography frequently downgraded the degree of MR.

Aged↗
PubMed2005

Late results of combined carotid and coronary surgery using actual versus actuarial methodology.

BACKGROUND: Controversy exists over the short-term results and long-term efficacy of concomitant coronary artery bypass grafting and carotid endarterectomy. Additionally, in this population actual versus actuarial assessment of nonfatal late events has not been previously reported. METHODS: Hospital records of 500 consecutive patients having concomitant carotid endarterectomy and coronary artery bypass grafting between 1979 and 2001 were reviewed, allowing at least 1 year of follow-up on all patients. Long-term nonfatal complications were assessed by actual and actuarial methods. RESULTS: Patient demographics revealed a mean age of 69 years; 74% (370 patients) were male; 75% (377 patients) presented with unstable coronary syndromes; 10% (50 patients) had an intraaortic balloon pump; and 66% (329 patients) were neurologically asymptomatic. Hospital mortality was 3.6% (18 patients). Significant multivariable predictors of hospital death were preoperative transient ischemic attack or myocardial infarction, and nonelective operation. Perioperative strokes were 4.6% (23 patients), of which 2.4% (12 patients) were ipsilateral and 2.2% (11 patients) were contralateral. Significant multivariable predictors of stroke were peripheral vascular disease and use of the right internal mammary artery. Ten-year actuarial survival was 43%. Ten-year actual versus Kaplan-Meier actuarial freedoms with 95% confidence limits from late events were myocardial infarction 87% (78% and 92%) versus 81% (75% and 87%); percutaneous coronary intervention 92% (85% and 96%) versus 89% (84% and 94%); reoperative coronary grafting 96% (89% and 99%) versus 94% (90% and 98%); total stroke 85% (77% and 91%) versus 82% (76% and 87%); ipsilateral stroke 90% (83% and 94%) versus 87% (82% and 92%); carotid endarterectomy 82% (73% and 88%) versus 75% (69% and 82%). CONCLUSIONS: Concomitant carotid and coronary artery surgery is safe and effective, particularly in preventing ipsilateral stroke, and neutralizes the impact of unilateral carotid stenosis on early and late stroke. Actual, not actuarial, methods more accurately represent the true risk of nonfatal late events.

Actuarial Analysis↗
PubMed2005

Right ventricular failure following cardiac surgery.

The management of right ventricular failure remains a significant challenge in cardiac surgery. To date, no single clinical study has encompassed all of the principles that can be called upon to manage this problem. This review deals with the physiological management components that may be of value to cardiac medical and surgical clinicians.

Animals↗
PubMed2005

Early and late results of the surgical correction of cardiac prosthetic paravalvular leaks.

BACKGROUND AND AIM OF THE STUDY: Although the incidence of paravalular leaks, the most common cause of non-structural dysfunction after valve replacement, is well defined, the results of their surgical correction are not. Given the growing enthusiasm for interventional catheter-based correction of paravalvular leaks, a current surgical baseline against which to compare these results is important. METHODS: All patients who had surgical correction of an aortic or mitral paravalvular leak unrelated to acute bacterial endocarditis between 1986 and 2001 were identified from a computerized registry. Hospital records were reviewed, and follow up data obtained. RESULTS: A total of 136 consecutive patients (73 males, 63 females; mean age 64 years) underwent surgical correction of a paravalvular leak. Of the valves, 44 (32%) were aortic and 92 (68%) mitral. More than one previous cardiac operation had been performed in 68 patients (50%). In 107 patients (79%; 32 aortic (73%), 75 mitral (82%)), the leak was the primary indication for reoperation, while for 29 patients (21%; 12 aortic (27%), 17 mitral (18%)) the correction was secondary to another cardiac procedure. In 65 patients (48%; 12 aortic (27%), 53 (58%) mitral)) the leak was repaired primarily, while in 71 patients (52%; 32 aortic (73%), 39 (42%) mitral)) the prosthesis was replaced. Operative mortality was 6.6% (n = 9). There were no significant multivariable predictors of hospital death. Perioperative stroke occurred in seven cases (5.1%), and hospital stay was >14 days in 40 patients (29%). The 10-year Kaplan-Meier survival was 30 (CI 20-39)%. Ten-year actual versus actuarial freedom from repeat paravalvular leak was 84 (CI 68-92)% versus 63 (CI 49-76)%. CONCLUSION: Surgical correction of cardiac paravalvular leaks can be performed with acceptable mortality and morbidity. Patients with surgically corrected paravalvular leaks have a limited life expectancy, but reasonable freedom from recurrent paravalvular leak.

Aortic Valve↗
PubMed2004

Initial experience with the AbioCor implantable replacement heart system.

OBJECTIVE: We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. METHODS: Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 +/- 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. RESULTS: There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. CONCLUSION: The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

Aged↗
PubMed2003

Efficacy of chordal cutting to relieve chronic persistent ischemic mitral regurgitation.

BACKGROUND: Mitral regurgitation (MR) conveys adverse prognosis in ischemic heart disease. Leaflet closure is restricted by tethering to displaced papillary muscles, and is, therefore, incompletely treated by annular reduction. In an acute ischemic model, we reduced such MR by cutting a limited number of critically positioned chordae to the leaflet base that most restrict closure but are not required to prevent prolapse. Whether this is effective without prolapse, recurrent MR, or left ventricular (LV) failure in chronic persistent ischemic MR, despite greater LV remodeling, remains to be established. Therefore, we studied 7 sheep with chronic inferobasal infarcts known to produce progressive MR over 2 months. In all of those sheep, after a mean of 4.1 months, the 2 central basal (intermediate) chordae were cut at the chronic ischemic MR stage. 3-Dimensional echo quantified MR, LV function, and valve geometry. Five other sheep were followed for a mean of 7.8+/-1.2 months after inferobasal infarction with chordal cutting. RESULTS: All 7 of the sheep with chronic ischemic MR (increased from 1.4+/-0.4 to 11.1+/-0.5 mL/beat, regurgitant fraction=39.0+/-4.2%, P<0.0001) showed anterior leaflet angulation at the basal chord insertion. Although end-systolic volume had doubled, cutting the 2 central basal chordae significantly decreased the MR to baseline (P<0.0001) without prolapse or decline in EF (41.1+/-1.5% to 42.6+/-1.6%, P=not significant [NS]). The five sheep with long-term follow-up showed no prolapse or MR, and no significant post-infarct decrease in LV ejection fraction (EF; 38.9+/-2.4% to 41.4+/-1.2%, P=NS). CONCLUSIONS: Cutting a minimum number of basal (intermediate) chordae can improve coaptation and reduce chronic persistent ischemic MR without impairing LVEF. No adverse effects were noted long-term after chordal cutting at the time of infarction.

Animals↗
PubMed2003

The AbioCor implantable replacement heart.

The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multisystem organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

Aged↗
PubMed2003

Omentum is highly effective in the management of complex cardiothoracic surgical problems.

OBJECTIVES: Vascularized, pedicled tissue flaps are often used for cardiothoracic surgical problems complicated by factors that adversely affect healing, such as previous irradiation, established infection, or steroid use. We reviewed our experience with use of the omentum in these situations to provide a yardstick against which results with other vascularized flaps (specifically muscle flaps) could be compared. METHODS: A retrospective review was undertaken of 85 consecutive patients in whom omentum was used in the chest. In 47 patients (group I), use of omentum was prophylactic to aid in the healing of closures or anastomoses considered to be at high risk for failure. In 32 patients (group II), omentum was used in the treatment of problems complicated by established infection. In 6 patients (group III), omentum was used for coverage of prosthetic chest wall replacements after extensive chest wall resection. RESULTS: Overall, omental transposition was successful in its prophylactic or therapeutic purpose in 88% of these difficult cases (75/85). Success with omentum was achieved for 89% of patients (42/47) in group I, 91% of patients (29/32) in group II, and 67% of patients (4/6) in group III. Three patients (3.5%) had complications of omental mobilization. Four patients (4.7%) died after the operation as a result of failure of the omentum to manage the problem for which it was used. CONCLUSIONS: Results with omental transposition compare favorably with published series of similarly challenging cases managed with muscle transposition. Complications of omental mobilization are rare. We believe that its unique properties render the omentum an excellent choice of vascularized pedicle in the management of the most complex cardiothoracic surgical problems.

Cardiac Surgical Procedures↗