HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Impact of surgical relief of outflow obstruction on thallium perfusion abnormalities in hypertrophic cardiomyopathy.

AbstractBACKGROUND:
To assess the impact of surgical relief of left ventricular outflow obstruction on myocardial perfusion abnormalities in patients with obstructive hypertrophic cardiomyopathy, 20 symptomatic patients who underwent a septal myectomy or mitral valve replacement were studied with assessment of myocardial perfusion during exercise by 201Tl emission computed tomography before and 6 months after surgery.
METHODS AND RESULTS:
Before surgery, 15 patients had myocardial perfusion defects during exercise that completely normalized at rest, one patient had both reversible and fixed perfusion defects, two patients had fixed defects only, and two patients had normal exercise and rest thallium scans. After surgical relief of left ventricular outflow obstruction (basal gradient reduced from 62 +/- 40 to 7 +/- 12 mm Hg, p less than 0.001; peak provokable gradient reduced from 131 +/- 27 to 49 +/- 36 mm Hg, p less than 0.001), repeat exercise thallium studies showed complete normalization of perfusion defects in 11 patients, including the two patients with fixed defects alone before surgery, and improvement in the magnitude and distribution of perfusion defects in five additional patients. This was associated with a significant reduction in the number of patients with reversible regional defects (five patients compared with 13 patients before surgery, p = 0.026) and of patients with endocardial hypoperfusion (four patients compared with 12 patients before surgery, p = 0.024). Furthermore, increased lung uptake of thallium was noted in five patients after surgery, compared with 12 patients before surgery (p = 0.055). Only two patients with reversible perfusion defects before surgery had unchanged postoperative studies. However, four patients acquired new fixed defects as a consequence of surgery, and two of these four had the greatest severity and distribution of left ventricular hypertrophy by echocardiography. These four patients experienced a substantially greater decrease in ejection fraction (-26 +/- 15%) after surgery than the remaining patients (-3 +/- 14%, p less than 0.01).
CONCLUSIONS:
Surgical relief of left ventricular outflow obstruction results in normalization or improvement of myocardial perfusion in the majority of patients with reversible and fixed perfusion defects by 201Tl scintigraphy. However, surgery may result in myocardial injury and scarring, with consequent decreased left ventricular ejection fraction in some patients.
AuthorsR O Cannon 3rd, V Dilsizian, P T O'Gara, J E Udelson, E Tucker, J A Panza, L Fananapazir, C L McIntosh, R B Wallace, R O Bonow
JournalCirculation (Circulation) Vol. 85 Issue 3 Pg. 1039-45 (Mar 1992) ISSN: 0009-7322 [Print] United States
PMID1537102 (Publication Type: Journal Article)
Chemical References
  • Thallium Radioisotopes
Topics
  • Cardiac Catheterization
  • Cardiomyopathy, Hypertrophic (diagnostic imaging, surgery)
  • Echocardiography
  • Exercise Test
  • Female
  • Heart (diagnostic imaging)
  • Heart Septum (surgery)
  • Heart Valve Prosthesis
  • Humans
  • Male
  • Middle Aged
  • Mitral Valve
  • Radionuclide Ventriculography
  • Thallium Radioisotopes
  • Tomography, Emission-Computed
  • Ventricular Function, Left (physiology)
  • Ventricular Outflow Obstruction (surgery)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: