Biomedical subjects

Gerald M Lawrie

Publications and source records attributed to Gerald M Lawrie.

8 recordsLinked to original sources

PubMed2006

Feasibility and intermediate term outcome of repair of prolapsing anterior mitral leaflets with artificial chordal replacement in 152 patients.

BACKGROUND: Mitral valve repair of the anterior leaflet has been more difficult than at other sites. METHODS: Between February 1983 and June 2004, 607 mitral valve repairs were performed on one service. Of these, 410 patients had leaflet repair procedures: 152 were anterior leaflet repairs; isolated in 94, and combined with posterior repair in 58 patients. The results in these patients were compared with the results of posterior leaflet repair in 258 patients. All patients received flexible ring annuloplasty. RESULTS: Age and sex of the anterior leaflet and posterior leaflet patients were similar: mean age 62.5 +/- 14.3, 62.9 +/- 14.9 years; males, 50.6%, p = not significant (NS). Preoperative ejection fraction was for anterior repairs 52.6 +/- 12.8%; posterior repair, 58.2 +/- 11.8%, p = NS. Coronary artery bypass was more frequently performed with anterior leaflet repair in 18 patients (19.1%) versus 45 (6.6%) for posterior leaflet repair (p = NS). The median number of chordae was similar in the anterior leaflet and posterior leaflet patients 4 (2-8), 4 (2-6), p = NS. Perioperative mortality was similar: anterior leaflet patients, 3.3% (2/94); posterior leaflet patients, 1.1% (2/258), p = NS. Hospital stay was for anterior leaflet patients and posterior leaflet patients: 12.86 +/- 13.3 vs 11.0 +/- 12.3, p = NS. Kaplan-Meier estimates of freedom from reoperation at 3 years were: for anterior leaflet patients, 91.9%: for posterior leaflet patients, 90.7%, p = 0.77. No structural polytetrafluoroethylene (PTFE) chordal failures were observed. Late echocardiographic data were obtained in 136 patients on 222 occasions at a mean of 3.2 +/- 3.34 years. Severe mitral regurgitation was present in 10 patients (7.3%). CONCLUSIONS: Repair of the anterior leaflet is facilitated by the use of PTFE replacement. Anterior leaflet repair can be performed reproducibly with the same results as posterior leaflet repair.

Aged↗

PubMed2006

Mitral valve: toward complete repairability.

During the last 50 years, there has been an exponential increase in our understanding of the structure and function of the mitral valve in health and disease. Large numbers of patients have undergone mitral-valve reparative procedures worldwide with variable results. In our initial 10-year experience in which traditional techniques were used for repair of mitral regurgitation, a 70% success rate was achieved. In 1995, a critical reappraisal of the common causes of failure to repair, or failure of repair and developed improved surgical approaches for these patients began. The conditions addressed were massive bileaflet prolapse ("Barlow's valves"); anterior leaflet prolapse; multisegment chordal failure; commissural accessory leaflet tissue prolapse; and leaflet destruction by endocarditis. A widely applicable standard technique was developed that the author and colleagues called the "American Correction." It emphasizes chordal replacement with polytetrafluoroethylene (PTFE) artificial chordae, importance of the line of apposition of the leaflets, and importance of simultaneous dynamic adjustment of the chordal length and anteroposterior dimension of the mitral annulus. In addition, use of multiple techniques in 30% of patients to complete the repair has been emphasized. These techniques resulted in a 90% repairability rate for all pathologies and 100% for myxomatous-mitral insufficiency. These techniques also have led to a decline in reoperation rates, and improved long-term durability. Continued evaluation with intraoperative and postoperative three-dimensional (3-D) echo provides further insights and refinement of mitral-repair techniques.

Clinical Trials as Topic↗

PubMed2005

Doppler estimation of left ventricular filling pressures in patients with mitral valve disease.

BACKGROUND: Conventional Doppler measurements have limitations in the prediction of left atrial pressure (LAP) in patients with mitral valve disease (MVD), given the confounding effect of valve area, left ventricular (LV) relaxation, and stiffness. However, the time interval between the onset of early diastolic mitral inflow velocity (E) and annular early diastolic velocity (Ea) by tissue Doppler imaging (TDI), T(E-Ea), which is well related to the time constant of LV relaxation (tau) in canine and clinical studies, is not subject to these variables. We therefore undertook this study to test its usefulness in a patient population. METHODS AND RESULTS: Two-dimensional Doppler and TDI echocardiography were performed simultaneously with right-heart catheterization in 51 consecutive patients (mean+/-SD age, 64+/-11 years) with MVD: 35 with moderately severe to severe mitral regurgitation (MR) and 16 with moderate to severe mitral stenosis (MS). Among several Doppler measurements, only the mitral E/A ratio, isovolumetric relaxation time (IVRT), and pulmonary venous Ar duration had significant relations with mean pulmonary capillary wedge pressure (PCWP). The ratio of IVRT to T(E-Ea) (for MR, r=-0.92; for MS, r=-0.88; both P<0.001) and the ratio of IVRT to tau (for MR, r=-0.74; for MS, r=-0.85; both P<0.001) had the best correlations with PCWP. In 54 repeat studies, including those performed after MV repair or replacement, these ratios tracked well the changes in PCWP and readily identified changes in mean PCWP by > or =5 mm Hg. A similar correlation was noted in 13 patients with atrial fibrillation (r=-0.92, P<0.01) and in a prospective group of 14 patients with MR (r=-0.93, P<0.001). CONCLUSIONS: The ratio of IVRT to T(E-Ea) or to tau can be readily applied for estimating mean PCWP in patients with MVD and can track changes in PCWP after valve surgery.

Aged↗

PubMed2004

Mitral valve repair in patients with low left ventricular ejection fractions: early and late results.

STUDY OBJECTIVES: This retrospective study was performed to examine the outcome of mitral valve repair (ie, mitral valvuloplasty [MVP]) in relation to preoperative low left ventricular ejection fraction (LVEF). DESIGN AND SETTINGS: From our series of 338 consecutive patients who underwent MVP between 1983 and 2001, we compared the course of 302 patients with preoperative LVEF of > 35% (group I) to that of 36 patients with LVEF of </= 35% (group II). RESULTS: Preoperatively, group II patients were more likely to be associated with ischemic heart disease (IHD) [p < 0.0002], and to have undergone emergency surgery (p < 0.02) and concomitant coronary artery bypass graft surgery (CABG) [p < 0.02]. The perioperative mortality rate was 8% for group II and 2% for group I (p < 0.03). On multivariate analysis, predictors of increased operative mortality were emergent operation (p < 0.001) and preoperative New York Heart Association (NYHA) class IV (p < 0.02). Predictors of overall mortality (early and late) included emergency operation (p < 0.02), preoperative NYHA class IV (p < 0.002), and IHD (p < 0.0001). Postoperatively, 78% of patients from both groups were in NYHA class I/II. The 5-year rate of freedom from reoperation was 89%. The estimated overall 5-year survival rate (early and late) was 82% for group I and 54% for group II (p < 0.02), and when associated with prior CABG, prior myocardial infarction, or concomitant CABG, it was 0%, 37%, and 63%, respectively, in group II. CONCLUSIONS: Good symptomatic relief and acceptable overall survival can be obtained in patients in both groups after they have undergone MVP, in the absence of serious comorbidities. Preoperative NYHA class IV and end-stage IHD increase early and late mortality, particularly in group II patients, in whom surgery may be a salvage effort only. Prognosis is dismal in group II patients who have previously undergone CABG. In chronic cases, an early referral for MVP electively before deterioration to end-stage heart disease would improve survival even in patients with low LVEF.

Adolescent↗

PubMed2003

Identification of hibernating myocardium with quantitative intravenous myocardial contrast echocardiography: comparison with dobutamine echocardiography and thallium-201 scintigraphy.

BACKGROUND: There are currently no data on the accuracy of intravenous myocardial contrast echocardiography (MCE) in detecting myocardial hibernation in man and its comparative accuracy to dobutamine echocardiography (DE) or thallium 201 (Tl(201)) scintigraphy. METHODS AND RESULTS: Twenty patients with coronary artery disease and ventricular dysfunction underwent MCE 1 to 5 days before bypass surgery and repeat echocardiography at 3 to 4 months. Patients also underwent DE (n=18) and rest-redistribution Tl(201) tomography (n=16) before revascularization. MCE was performed using continuous Optison infusion (12 to 16 cc/h) with intermittent pulse inversion harmonics and incremental triggering (1:1 to 1:8). Myocardial contrast intensity (MCI) replenishment curves were constructed to derive quantitative MCE indices of blood velocity and flow. Recovery of function occurred in 38% of dysfunctional segments. MCE parameters of perfusion in hibernating myocardium were similar to segments with normal function and higher than dysfunctional myocardium without recovery of function (P<0.001). The best MCE parameter for predicting functional recovery was Peak MCIxbeta, an index of myocardial blood flow (area under the curve, 0.83). MCE parameters were higher in segments with contractile reserve and Tl(201) uptake > or =60% (P<0.05) and identified viable segments without contractile reserve by DE. The sensitivity of Peak MCIxbeta >1.5 dB/s for recovery of function was 90% and was similar to Tl(201) scintigraphy (92%) and any contractile reserve (80%); specificity was higher than for Tl(201) and DE (63%, 45%, and 54%, respectively; P<0.05). CONCLUSIONS: MCE with intravenous contrast identifies myocardial hibernation in humans. Prediction of viable myocardium with MCE is best using quantification of myocardial blood flow and provides improved accuracy compared with DE and Tl(201) scintigraphy.

Aged↗

PubMed2003

Surgical outcome in 85 patients with primary cardiac tumors.

BACKGROUND: We present a large, single institution experience with adult cardiac tumors and address factors affecting outcome. METHODS: A retrospective review was made of all patients who underwent surgery for primary cardiac tumors from April 1975 through August 2002. RESULTS: Eighty-five patients (33 male and 52 female) with a mean age of 54 years were identified with follow-up available for 80 (94%) patients. There were 68 (80%) benign tumors and 17 (20%) malignant tumors. Three tumors recurred and were resected giving a total of 88 surgeries. All benign tumors were grossly resected and the extent of resection for malignant disease ranged from 14 (78%) gross resections and 3 (17%) debulkings to 1 (5%) biopsy. There were 4 (5%) early hospital deaths. Median survival was 9.6 months and 322 months for patients with malignant and benign diseases, respectively. Significant predictors of long-term mortality were malignant disease (P <0.0001) and New York Heart Association class (P <0.03). CONCLUSIONS: Surgical resection provides excellent outcome in patients with benign cardiac tumors. Malignant tumors continue to pose a challenge with good local tumor control but limited survival owing to metastatic disease.

Adolescent↗

PubMed2002

Microvascular structural correlates of myocardial contrast echocardiography in patients with coronary artery disease and left ventricular dysfunction: implications for the assessment of myocardial hibernation.

BACKGROUND: Myocardial contrast echocardiography (MCE) has been used to evaluate myocardial viability. There are no data, however, on the pathological determinants of myocardial perfusion by MCE in humans and the implications of such determinants. METHODS AND RESULTS: MCE was performed in 20 patients with coronary artery disease and ventricular dysfunction within 24 hours before myocardial biopsy at surgery using a continuous Optison infusion (12 to 16 cc/h), with intermittent pulse inversion harmonics and incremental triggering. Peak myocardial contrast intensity (MCI) and the rate of increase in MCI (beta) were quantitated. Thirty-six transmural myocardial biopsies (2 per patient) were obtained by transesophageal echocardiography. Total microvascular (<100 microm) density, capillary density and area, arteriolar and venular density, and percent collagen content were quantitated with immunohistochemistry. Peak MCI correlated with microvascular density (r=0.59, P<0.001) and capillary area (r=0.64, P<0.001) and inversely correlated with percent collagen content (r=-0.45, P=<0.01). The best relation was observed when the ratio of peak MCI in the 2 biopsied segments in each patient was compared with the ratio of microvascular density and capillary area (r=0.84 and 0.87, respectively; P<0.001). A significant overlap in microvascular density was seen between segments with and without recovery of function. The new MCE indices of blood velocity (beta) and flow (peak MCIxbeta) better identified recovery of function compared with microvascular density and the sole use of peak MCI. CONCLUSIONS: Microvascular integrity is a significant determinant of maximal MCI in humans. MCE indices of blood velocity and flow are important parameters that predict recovery of function after revascularization.

Aged↗

PubMed2000

Mitral Valve Repair: the Multimodal Approach and the Role of Minimally Invasive Procedures.

In recent years mitral valve repair has gained increasing acceptance as the preferred treatment for mitral insufficiency. Mitral valve repair has many advantages. The surgical risk is lower than prosthetic valve replacement. Improved preservation of left ventricular function due to maintenance of the papillary muscle - mitral annular continuity - has been demonstrated. Thromboembolism is rare after mitral repair in patients in sinus rhythm. These patients receive no coumadin and thus are free from bleeding complications. The repaired valves have been shown to have durability comparable to or better than prosthetic valves.

Journal Article↗