Document Detail

Functional comparison of transmyocardial revascularization by mechanical and laser means.
MedLine Citation:
PMID:  11789783     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: As a result of the clinical benefit observed in angina patients treated by transmyocardial revascularization (TMR) with a laser, interest in mechanical TMR has been renewed. Although the injury induced by mechanical TMR is similar to laser TMR, the resultant impact on myocardial contractility is unknown. The purpose of this study was to determine whether mechanical TMR improves ventricular function as compared with laser TMR in chronically ischemic myocardium. METHODS: After establishing an area of chronic myocardial ischemia, 25 domestic pigs were randomized to treatment by: excimer laser (group I), a hot needle (50 degrees C) (group II), a normothermic needle (group III), an ultrasonic needle (40 KHz) (group IV), or no treatment (group V). All devices create a transmural channel of the same diameter; 22 +/- 1 transmural channels were created in each animal. Regional myocardial contractility was assessed by measuring ventricular wall thickening at rest and with dobutamine stress echocardiography. Six weeks after revascularization, the animals were restudied at rest and with stress. Postsacrifice and histologic analysis of angiogenesis and TMR effects was then assessed. RESULTS: Laser TMR provided significant recovery of ischemic myocardial function. This improvement in contractility after laser TMR was a 75% increase over the baseline function of the ischemic zone (p < 0.01). Mechanical TMR provided no significant improvement in function posttreatment. In fact, TMR achieved with an ultrasonic needle demonstrated a 40% worsening of the contractility versus the pretreatment baseline (p < 0.05). Histologic analysis demonstrated a significant increase in new blood vessels in the ischemic zone after laser TMR, which was not demonstrated for any of the other groups (p < 0.05). Additionally, evaluation of the mechanical TMR channels demonstrated significant scarring, which correlated with the functional results. CONCLUSIONS: Using devices to create an injury analogous to the laser, mechanical TMR failed to improve the function of chronically ischemic myocardium. Only laser TMR significantly improved myocardial function.
K A Horvath; N Belkind; I Wu; R Greene; J Doukas; J W Lomasney; D D McPherson; D A Fullerton
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The Annals of thoracic surgery     Volume:  72     ISSN:  0003-4975     ISO Abbreviation:  Ann. Thorac. Surg.     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2002-01-14     Completed Date:  2002-01-31     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  15030100R     Medline TA:  Ann Thorac Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1997-2002     Citation Subset:  AIM; IM    
Division of Cardiothoracic Surgery, Northwestern University Medical School, Chicago, Illinois 60611, USA.
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MeSH Terms
Coronary Vessels / pathology
Electrosurgery / methods*
Heart Ventricles / pathology,  surgery
Laser Therapy / methods*
Myocardial Contraction / physiology
Myocardial Ischemia / pathology,  surgery*
Myocardial Revascularization / methods*
Neovascularization, Physiologic / physiology
Ultrasonic Therapy / methods*

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