Clinical evidence for myocardial derecruitment downstream from severe stenosis: Pressure-flow control interaction

Gianmario Sambuceti, Mario Marzilli, Andrea Mari, Cecilia Marini, Paolo Marzullo, Roberto Testa, Isabella Raugei, Micaela Papini, Mathis Schluter, Antonio L'Abbate

Research output: Contribution to journalArticle

Abstract

To verify the interaction between coronary pressure (CP) and blood flow (CBF) control, we studied nine candidates for angioplasty of an isolated lesion of the left anterior descending coronary artery [i.e., percutaneous transluminal coronary angioplasty (PTCA)]. CBF (i.e., flow velocity x coronary cross-sectional area at the Doppler tip) and CP were monitored during washout of 2-5 mCi of 133Xe after bolus injection into the left main artery before and after PTCA. Xe mean transit time (MTT) was calculated as the area under the time-activity curve, acquired by a gamma camera, divided by the dose obtained from a model fit of the Xe curve in the anterior wall. CBF response to intracoronary adenosine (2 mg) was also assessed. PTCA increased baseline CBF (from 14.5 ± 9.4 to 20 ± 8 ml/min, P <0.01), coronary flow reserve (from 1.52 ± 0.24 to 2.33 ± 0.8, P <0.01), and CP (from 64 ± 9 to 100 ± 10 mmHg, P <0.05). MTT decreased from 89 ± 32 to 70 ± 19 s (P <0.05) after PTCA; however, MTT and CBF changes were not correlated (r = -0.09, not significant). Inasmuch as MTT is the ratio of distribution volume to CBF, MTT x CBF was used as an index of perfused myocardial volume. Volume increased after PTCA from 23 ± 18 to 56 ± 30 ml. A direct correlation was observed between the percent increase in distal CP and percent increase in perfused volume (r = 0.91, P <0.01). Thus low CP was not associated with exhaustion of flow reserve but, rather, with reduction of perfused myocardial volume. These data suggest that, in the presence of a severe coronary stenosis, derecruitment of vascular units occurs that is proportional to the decrease in driving pressure. Residual perfused units maintain a vasomotor tone, thus explaining the paradoxical persistence of coronary reserve.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number6 48-6
Publication statusPublished - 2000

Keywords

  • Autoregulation
  • Coronary angioplasty
  • Coronary artery disease
  • Coronary circulation
  • Microcirculation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Clinical evidence for myocardial derecruitment downstream from severe stenosis: Pressure-flow control interaction'. Together they form a unique fingerprint.

  • Cite this