Observation of Regional Cerebral Blood Flow Measurement Using 133Xe Inhalation Before and After Enhanced External Counterpulsation in Patients with Cerebral Infarction
Author Information and Affiliation
Gu Dexiang, Yang Sijun, Li Fei
Department of Neurology, The Second Hospital of Shanghai Textile Industry Bureau, Shanghai, China
Source: usecp.com (Compiled and reviewed by Gong Guoji)
Abstract
Objective: To observe the effects of Enhanced External Counterpulsation (ECP) on regional cerebral blood flow (rCBF) in patients with acute cerebral infarction.
Methods: This study enrolled 81 hospitalized patients in the acute phase of cerebral infarction, randomly divided into a Treatment Group (n=50) and a Control Group (n=31). Both groups received intravenous drip infusions of Salvia miltiorrhiza injection (Danshen) for 12 days. The Treatment Group additionally received daily ECP treatment for 1 hour per session. rCBF was measured using the 133Xe inhalation method within 5 days before treatment and within 3 days after treatment completion.
Results: In the Treatment Group following ECP, the mean rCBF increased significantly: the left hemisphere increased from 45.5 mL/min/100g to 53.1 mL/min/100g (P<0.01); and the right hemisphere increased from 47.1 mL/min/100g to 54.1 mL/min/100g (P<0.01). The Control Group showed a slight decrease or no significant change in rCBF. Post-treatment rCBF in the Treatment Group was significantly higher than in the Control Group (both hemispheres P<0.01).
Conclusion: ECP treatment effectively increases whole-brain blood flow, including the ischemic focus, and maintains the established blood supply level even after treatment cessation. ECP is a reliable, effective, and safe therapeutic measure that promotes the recovery of the ischemic penumbra surrounding the lesion, and its use should be broadly promoted for patients with cerebral infarction.
Methods and Materials
1. Regional Cerebral Blood Flow (rCBF) Measurement
Equipment and Procedure: rCBF was measured using a cerebral blood flow monitoring system developed by the Shanghai Naval Medical Research Institute, coupled with an American IBM computer system. Measurements were taken at a controlled room temperature of 14°C to 16°C while the patient rested supine. Twenty-eight standard sodium iodide detectors were used, with the probes in close contact with the scalp. The patient inhaled a mixture of 133Xe and air (equivalent to 4 mCi) through a sealed mask for 1 minute. The cerebral clearance curve was then monitored for 12 minutes, and the connected computer calculated the rCBF for different brain regions. The results were stored, analyzed, and topographical maps were generated by an automatic recording system.
2. Study Participants
Case Inclusion: All cases were inpatients admitted during the acute phase of cerebral infarction between June 1994 and November 1995. All patients were confirmed by head CT scans to have single or multiple intracranial low-density lesions (cases without obvious lesions were excluded).
Inclusion Criteria: Upon admission, patients were conscious, had hemiplegia with muscle strength Grade II or III or higher in the affected limb, were in a stable general condition to tolerate ECP treatment, and had no significant concurrent complications or comorbidities.
Grouping and Baseline Characteristics
| Group | Number of Patients (n) | Male (n) | Female (n) | Mean Age (y) | Single CT Lesion (n) | Multiple CT Lesions (n) |
|---|---|---|---|---|---|---|
| Treatment Group | 50 | 20 | 30 | 65 | 36 | 14 |
| Control Group | 31 | 14 | 17 | 69 | 18 | 13 |
3. Treatment Protocol
Grouping and Basic Medication: Patients were randomly divided into a Treatment Group and a Control Group. Both groups received daily intravenous drip infusions of the same dose of Salvia miltiorrhiza injection (Danshen) for a total of 12 days.
ECP Treatment: The Treatment Group additionally received ECP treatment once daily for 1 hour per session, with counterpulsation pressure set between 0.04 MPa and 0.08 MPa. No other additional treatments were administered to either group during this period.
rCBF Measurement Timing: rCBF measurements were conducted for both groups within 5 days prior to treatment and within 3 days after treatment completion.
Results
1. Comparison of rCBF Between Treatment and Control Groups Before and After Treatment
Table 1 shows the comparison of mean rCBF in the left and right hemispheres between the Treatment and Control groups before and after treatment.
Table 1. Comparison of Mean rCBF Before and After Treatment Between Groups
| Group | Pre-Treatment Left Hemisphere (mL/min/100g) | Post-Treatment Left Hemisphere (mL/min/100g) | Pre-Treatment Right Hemisphere (mL/min/100g) | Post-Treatment Right Hemisphere (mL/min/100g) |
|---|---|---|---|---|
| Treatment Group | 45.5 | 53.1 | 47.1 | 54.1 |
| Control Group | 48.9 | 45.0 | 50.4 | 45.6 |
Statistical Analysis:
- Comparison of post-treatment mean rCBF (Left Hemisphere): P<0.01 (t=2.65109)
- Comparison of post-treatment mean rCBF (Right Hemisphere): P<0.01 (t=3.01005)
2. Comparison of rCBF in the Treatment Group Before and After Treatment
Table 2 shows the change in mean rCBF within the Treatment Group following ECP therapy.
Table 2. Comparison of Mean rCBF Before and After Treatment in the Treatment Group
| Cerebral Hemisphere | Pre-Treatment (mL/min/100g) | Post-Treatment (mL/min/100g) |
|---|---|---|
| Left Hemisphere | 45.5 | 53.1 |
| Right Hemisphere | 47.1 | 54.1 |
Statistical Analysis:
- Pre- vs. Post-treatment mean rCBF (Left Hemisphere): P<0.01 (t=3.03988)
- Pre- vs. Post-treatment mean rCBF (Right Hemisphere): P<0.01 (t=2.73334)
Discussion
1. ECP Increases Whole-Brain Blood Flow
The observation of rCBF using the 133Xe inhalation method before and after ECP treatment demonstrates that ECP significantly increases the total cerebral blood flow, including blood flow to the ischemic focus. The post-treatment rCBF in the Treatment Group reached the lower limit of the normal range (approximately 55 mL/min/100g). Crucially, no evidence of "steal phenomenon"—a risk associated with some vasodilators—was observed. This suggests ECP is a reliable and effective therapeutic approach for cerebral infarction.
2. Protection of the Ischemic Penumbra
Since ECP increases cerebral blood flow, including in ischemic areas, and is easy to administer and safe, it should be initiated as early as possible in eligible cerebral infarction patients. The increased blood flow supports the perfusion of the lesion area and, more importantly, promotes the functional recovery of the ischemic penumbra, mitigating further damage caused by ischemia in the surrounding tissue.
3. Sustained Improvement and Mechanism
If ECP merely provided a transient mechanical increase in blood flow during the session, rCBF should rapidly return to baseline upon cessation of therapy. However, our results show that the rCBF was maintained at the enhanced level achieved during treatment. This strongly suggests that ECP likely promotes the opening of intracranial blood vessels and facilitates the establishment of collateral circulation around the ischemic region, leading to sustained improvement in cerebral tissue perfusion, while simultaneously avoiding the risk of steal phenomenon seen with some pharmacological vasodilators.
4. Role of Improved Cardiac Function
Another significant factor contributing to the increase in cerebral blood flow may be the improvement in cardiac function. Although patients with cerebral infarction may not present with obvious signs or symptoms of heart disease, some degree of cardiac insufficiency is often present. ECP treatment concurrently improves cardiac function, which indirectly leads to an increase in cerebral blood flow.
5. Clinical Application
ECP is indicated for the acute, recovery, and sequelae stages of cerebral infarction. Given its ease of use, simple conditions, and safety profile, its application should be widely promoted.