Effect of a Mechanical vs a Pharmacologic Increase in Aortic Pressure on Coronary Blood Flow and Thrombolysis Induced by IV Administration of a Thrombolytic Agent (Results)

In: Aortic Pressure

9 Jan 2014

Effect of a Mechanical vs a Pharmacologic Increase in Aortic Pressure on Coronary Blood Flow and Thrombolysis Induced by IV Administration of a Thrombolytic Agent (Introduction)

Table 1 illustrates mean (±SE) values of hemodynamic effects of coronary thrombosis in all eight dogs. Note that following clot, systolic BP, pulmonary artery diastolic pressure, and heart rate remained constant and CO decreased (p<0.005). Female Pink Viagra Canadian

Figure 2 depicts the effects of clot on blood flow in the left anterior descending coronary artery. Note that following injection of clot, mean left anterior descending coronary artery flow decreased 17% (p<0.01). The magnitude of this decrease indicates that total occlusion did not occur at the level of the flow probe and that either the injected blood clot migrated more distally into the artery or lodged proximally and subtotally occluded the arteiy. Since the blood clot is soft and injected through a small caliber catheter, we favor the former possibility.

Table 2 demonstrates mean (±SE) values before and during norepinephrine infusion as well as before and during Fogarty catheter inflation. Note that measured values were similar both before norepinephrine infusion and before Fogarty catheter inflation, indicating stability of the preparation over time.

Figure 2. The effect of clot on blood flow in the left anterior descending (LAD) coronary artery.

As dictated by experimental design, systolic BPs increased to a similar level with both interventions. The values for aortic diastolic pressure are also depicted in Table 2. The diastolic aortic pressure was slightly higher during balloon inflation (12%, p<0.05). Note that CO was higher during norepinephrine infusion than prior to norepinephrine infusion (p<0.01). As well, CO was higher during norepinephrine infusion than during balloon inflation (p<0.01). Heart rate also differed in the same way (both p<0.01).

Figure 3 plots mean (±SE) values and illustrates the effect of a mechanical and pharmacologic increase in left anterior descending coronary artery inflow pressure on left anterior descending artery blood flow. Note that compared with hypotension (postphlebotomy), both interventions significantly increased flow (p<0.01). Also note that values for left anterior descending coronaiy blood flow are similar with norepinephrine and Fogarty catheter inflation.

Figure 4 plots mean (±SE) values and depicts the rates of coronary thrombolysis obtained during norepinephrine infusion and Fogarty catheter inflation. Rates of clot lysis were similar with both interventions. The correlation coefficients (r) obtained by linear regression analysis of the count-time coordinates obtained during the two 15-min intervals of rtPA infusion indicate that they are well described by a line. The mean (±SE) r values obtained during norepinephrine infusion and Fogarty catheter inflation were 0.98±0.004 and 0.98 ±0.0053, respectively. All r values were significant to at least p<0.001.

Table 1—Hemodynamic Effects of Clot

Preclot Postclot
BP, mm Hg
Systolic 108 ±6 108±6
Diastolic 90 ± 8 91±7
RAP, mm Hg 4±0.6 5±1.0
Heart rate, beats/min 136±11 129±10
CO, L/min 2.5±1.9 2.0±0.1
PA diastolic pressure, mm Hg 11 ±2 12±3

Table 2—Hemodynamic Effects of Treatment

BeforeNE NE Before Balloon Inflation BalloonInflation
BP, mm Hg
Systolic 69±3 122±4 73±4 135 ±7
Diastolic 50±3 93±2 53 ±3 106±3
PAP, mm Hg, 10±1 11±1 10±1 12±1
diastolic
RAP, mm Hg 3±0.4 2.3±0.6 3±0.6 3±0.6
CO, L/min 1.4±0.1 2.7±0.3 1.3±0.1 0.9±0.1
HR, beats/m in 135±10 184±11 145 ±8 133±5.7
SV, mL/beats 10±1 15±2 9±1 7±1

figure-1

Figure 1. Illustration of the experimental preparation. LAD = left anterior descending coronary artery; CIRC=left circumflex coronary artery; PA=pulmonary artery. Also illustrated is the flow probe located close to the tip of the catheter.

figure-2

Figure 2. The effect of clot on blood flow in the left anterior descending (LAD) coronary artery.

figure-3

Figure 3. The effect of norepinephrine (NE) infusion and Fogarty catheter inflation on blood flow in the left anterior descending (LAD) coronary artery.

figure-4

Figure 4. The rates of coronary thrombolysis obtained with IV administration of rtPA during norepinephrine (NE) infusion and during Fogarty catheter inflation. Values are expressed as mean±SE. For discussion, see text.


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