| 1. |
- Gonon, Adrian, et al.
(författare)
-
Effects of thoracic epidural analgesia on exercise-induced myocardial ischaemia in refractory angina pectoris
- 2019
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : WILEY. - 0001-5172 .- 1399-6576. ; 63:4, s. 515-522
-
Tidskriftsartikel (refereegranskat)abstract
- Background Thoracic epidural analgesia (TEDA) was offered to patients with refractory angina pectoris. Our primary objectives were to evaluate TEDAs influence on quality of life (QoL, base for power analysis), and hypothesising that TEDA with bupivacaine during 1 month counteracts exercise-induced myocardial hypoperfusion and increase physical performance. Methods Patients with refractory angina and exercise inducible hypoperfusion, as demonstrated by myocardial perfusion imaging (MPI), were randomised to 1-month treatment with TEDA with bupivacaine (B-group, n = 9) or saline (P-group, n = 10) in a double-blind fashion. MPI and bicycle ergometry were performed before TEDA and after 1 month while subjective QoL on a visual analogue scale (VAS) reported by the patients was checked weekly. Results During this month VAS (mean [95%CI]) increased similarly in both groups (B-group from 33 [18-50] to 54 [30-78] P P amp;lt; 0.05). The B-group reduced their exertional-induced myocardial hypoperfusion (from 32% [12-52] to 21% [3-39]; n = 9; P amp;lt; 0.05), while the P-group showed no significant change (before 21% [6-35]; at 1 month 23% [6-40]; n = 10). MPI at rest did not change and no improvement in physical performance was detected in neither of the groups. Conclusions In refractory angina, TEDA with bupivacaine inhibits myocardial ischaemia in contrast to TEDA with saline. Regardless of whether bupivacaine or saline is applied intermittently every day, TEDA during 1 month improves the quality of life and reduces angina, even when physical performance remains low. A significant placebo effect has to be considered.
|
|
| 2. |
- Grishenkov, Dmitry, 1983-, et al.
(författare)
-
In search of the optimal ultrasound heart perfusion imaging platform
- 2015
-
Ingår i: Journal of ultrasound in medicine. - : Wiley. - 0278-4297 .- 1550-9613. ; 34:9, s. 1599-1605
-
Tidskriftsartikel (refereegranskat)abstract
- ObjectiveQuantification of the myocardial perfusion by contrast echocardiography (CEC) remains a challenge. Existing imaging phantoms used to evaluate the performance of ultrasound scanners do not comply with perfusion basics in the myocardium, where perfusion and motion are inherently coupled.MethodsTo contribute towards an improvement, we developed a CEC perfusion imaging platform based on isolated rat heart coupled to the ultrasound scanner. Perfusion was assessed using three different types of contrast agent: dextran-based Promiten®, phospholipid-shelled SonoVue®, and polymer-shelled MB-pH5-RT. The myocardial video-intensity was monitored over time from contrast administration to peak and two characteristic constants were calculated using exponential fit (A representing capillary volume and b representing inflow velocity).ResultsAcquired experimental evidence demonstrates that the application of all three types of contrast agent allow ultrasonic estimation of myocardial perfusion in the isolated rat heart. Video-intensity maps show that an increase in contrast concentration increases the late plateau values, A, mimicking increased capillary volume. Estimated values of the flow, proportional to Axb, increase when the pressure of the perfusate column increases from 80 to 110 cm of water. This finding is in agreement with the true values of the coronary flow increase measured by the flowmeter attached to the aortic cannula.ConclusionsThe described CEC perfusion imaging platform holds promise for standardized evaluation and optimization of ultrasound contrast perfusion imaging where real time inflow curves at low acoustic power semi-quantitatively reflect coronary flow.
|
|
| 3. |
- Grishenkov, Dmitry, 1983-, et al.
(författare)
-
Ultrasound contrast agent loaded with nitric oxide as a theranostic microdevice : Theranostic contrast agent loaded with nitric oxide
- 2015
-
Ingår i: Drug Design, Development and Therapy. - 1177-8881. ; 9, s. 2409-2419
-
Tidskriftsartikel (refereegranskat)abstract
- The current study describes novel multifunctional polymer-shelled microbubbles (MBs) loaded with nitric oxide (NO) for integrated therapeutic and diagnostic applications, i.e. theranostics, of myocardial ischemia. We used gas filled MBs with an average diameter of 4 µm stabilized by a biocompatible shell of poly(vinyl)alcohol. In vitro acoustic tests showed a sufficient enhancement of the backscattered power (20 dB) acquired from the MBs suspension. The values of attenuation coefficient (0.8 dB/cm MHz) and phase velocities (1517 m/s) were comparable to those reported for the soft tissue. Moreover, polymer MBs demonstrate increased stability compared to clinically approved contrast agents with fracture threshold of about 900 kPa. In vitro chemiluminescence measurements demonstrated that dry powder of NO-loaded MBs releases its gas content in about 2 hours following an exponential decay profile with an exponential time constant equal 36 min. The application of high power ultrasound pulse (MI=1.2) on the MBs resuspended in saline decreases the exponential time constant from 55 to 4 min in air saturated solution and from 17 to 10 min in degased solution. Thus, ultrasound-triggered release of NO is achieved. Cytotoxicity tests indicate that phagocytosis of the MBs by macrophages starts within 6 to 8 hours. This is suitable time for initial diagnostics, treatment and monitoring of the therapeutic effect using single injection of the proposed multifunctional MBs.
|
|
