COMPARATIVE STUDY OF TOPICAL USE OF VASODILATING SOLUTIONS

Lasting Effects of Surgically Used Topical Vasodilators on DIEP Artery Vascular Function

BACKGROUND

 Surgeons routinely apply papaverine, lidocaine, or verapamil to produce acute vasodilation and prevent vasospasms during microvascular surgeries. There is evidence that topical vasodilators may induce postoperative endothelial and smooth muscle dysfunction, which would present after the acute vasodilatory effects of the topical drugs wear off. Therefore, the purpose of the current study was to evaluate the lasting effects of papaverine, lidocaine, and verapamil on human deep inferior epigastric perforator artery vasodilatory function after the acute effects of the topical drugs had worn off.

METHODS

 Deep inferior epigastric arterial samples were obtained from 12 patients during surgery. Each artery was dissected into four rings which where incubated for 1 minute in either physiological saline solution (control), papaverine (30 mg/mL), lidocaine (20 mg/mL), or verapamil (2.5 mg/mL), followed by a 2-hour washout. Endothelial-dependent and -independent vasorelaxation were then assessed by the isometric tension responses to acetylcholine or sodium nitroprusside, respectively.

RESULTS

 Peak acetylcholine-evoked vasorelaxation (mean ± standard deviation) was not different between control (62 ± 23%) and lidocaine (57 ± 18%, p = 0.881), but was reduced (all p < 0.002) in papaverine (22 ± 27%) and verapamil (22 ± 20%). Peak sodium nitroprusside-evoked vasorelaxation was not different (all p > 0.692) among control (132 ± 35%), lidocaine (121 ± 22%), and verapamil (127 ± 22%), but was less in papaverine (104 ± 41%; p = 0.045) than control.

CONCLUSION

 Surgically used doses of papaverine and verapamil, but not lidocaine, have lasting negative effects on arterial vasodilatory function despite the acute effects of the drugs having worn off. These findings, in conjunction with the spasmolytic properties of each drug, may help guide the selection of an optimal topical vasodilator for use during microvascular surgeries.

Vasodilating Effects of Antispasmodic Agents and Their Cytotoxicity in Vascular Smooth Muscle Cells and Endothelial Cells-Potential Application in Microsurgery

This study aimed to elucidate the vasodilatory effects and cytotoxicity of various vasodilators used as antispasmodic agents during microsurgical anastomosis. Rat smooth muscle cells (RSMCs) and human coronary artery endothelial cells (HCAECs) were used to investigate the physiological concentrations and cytotoxicity of various vasodilators (lidocaine, papaverine, nitroglycerin, phentolamine, and orciprenaline). Using a wire myograph system, we determined the vasodilatory effects of each drug in rat abdominal aortic sections at the concentration resulting in maximal vasodilation as well as at the surrounding concentrations 10 min after administration. Maximal vasodilation effect 10 min after administration was achieved at the following concentrations: lidocaine, 35 mM; papaverine, 0.18 mM; nitroglycerin, 0.022 mM; phentolamine, 0.11 mM; olprinone, 0.004 mM. The IC₅₀ for lidocaine, papaverine, and nitroglycerin was measured in rat abdominal aortic sections, as well as in RSMCs after 30 min and in HCAECs after 10 min. Phentolamine and olprinone showed no cytotoxicity towards RSMCs or HCAECs. The concentrations of the various drugs required to achieve vasodilation were lower than the reported clinical concentrations. Lidocaine, papaverine, and nitroglycerin showed cytotoxicity, even at lower concentrations than those reported clinically. Phentolamine and olprinone show antispasmodic effects without cytotoxicity, making them useful candidates for local administration as antispasmodics.

The Efficacy of Hydrodilatation for the Prevention of Vasospasm following Microsurgical Anastomosis

INTRODUCTION

 Vasospasm is a major problem following microsurgical reconstruction which can result in the partial or complete loss of the flap tissue. The aim of this study was to investigate the efficiency of hydrodilatation for the prevention of vasospasm.

MATERIAL AND METHODS

 Thirty male Wistar rats were used for this experimental study. Femoral arteries of were exposed, photographed, and transected. In group 1, group 2, and group 3 papaverine solution, hydrodilatation, and minimal mechanical dilatation (control group) was performed, respectively. The anastomosis was completed and the arteries were photographed again 10 minutes after completion of the anastomosis. Following 7-day period samples for transmission electron microscopy (TEM) and light microscopy were obtained.

RESULTS

 The mean vessel diameters prior to transection were 0.43, 0.45, and 0.52 mm in the papaverine, hydrodilatation, and control groups, respectively. The mean vessel diameter 10 minutes following the completion of anastomosis was 0.76, 0.75, and 0.51 mm in the papaverine, hydrodilatation, and control groups, respectively. Median score for papaverine group regarding histological parameters of regular endothelial lining and lumen, neutrophil infiltration, vascular congestion, and edema in tunica adventitia was 2, 3, 2, and 3 positive, respectively. Median score for the papaverine group regarding histological parameters of regular endothelial lining and lumen, neutrophil infiltration, vascular congestion, and edema in tunica adventitia was 3, 3, 3, and 3 positive, respectively. All the histological scores were negative in the control group. The difference between the control group and the experiment groups 1 and 2 was significant regarding all four histological parameters (p < 0.05).

CONCLUSION

 Hydrodilatation and papaverine application were both effective in preventing vasospasm following microsurgical intervention but papaverine caused slightly less damage to the endothelial lining and less edema in the tunica adventitia when compared with the hydrodilatation. Hydrodilatation group showed a vasodilatory effect that was statistically similar to that of papaverine, which has a proven efficacy.

Wire Myography for Continuous Estimation of the Optimal Concentration of Topical Lidocaine as a Vasodilator in Microsurgery

BACKGROUND

 Intraoperative vasospasm during reconstructive microvascular surgery is often unpredictable and may lead to devastating flap loss. Therefore, various vasodilators are used in reconstructive microsurgery to prevent and relieve vasospasm. Lidocaine is a vasodilator commonly used in microvascular surgery. Although many reports have described its in vitro and in vivo concentration-dependent vasodilatory effects, limited studies have examined the pharmacological effects of lidocaine on blood vessels in terms of persistence and titer.

METHODS

 In this study, the vasodilatory effect of lidocaine was examined by using the wire myograph system. Abdominal aortas were harvested from female rats, sliced into rings of 1-mm thickness, and mounted in the wire myograph system. Next, 10, 5, 2, and 1% lidocaine solutions were applied to the artery, and the change in vasodilation force, persistence of the force, and time required to reach equilibrium were measured.

RESULTS

 The vasodilatory effect was confirmed in all groups following lidocaine treatment. Although strong vasodilation was observed in the 10% lidocaine group, it was accompanied by irreversible degeneration of the artery. Vasodilation in the 1% lidocaine group was weaker than that in the other groups 500 seconds after lidocaine addition (p < 0.05). Between the 5 and 2% lidocaine groups, 5% lidocaine showed a stronger vasodilatory effect 400 to 600 seconds after lidocaine addition (p < 0.01); however, there was no significant difference in these groups after 700 seconds. Additionally, there was no difference in the time required for the relaxation force to reach equilibrium among the 5, 2, and 1% lidocaine groups.

CONCLUSION

 Although our study confirmed the dose-dependent vasodilatory effect of lidocaine, 5% lidocaine showed the best vasodilatory effect and continuity with minimal irreversible changes in the arterial tissue.

Comparing the Outcomes of Different Agents to Treat Vasospasm at Microsurgical Anastomosis during the Papaverine Shortage

BACKGROUND

Papaverine remains popular for treating intraoperative vasospasm, but the recent shortage has forced surgeons to trial antispasmodic agents unproven in microsurgery but commonly used in other body areas. During this shortage, the authors have used topical lidocaine and nicardipine to break intraoperative vasospasm. This study aims to analyze the outcomes of these medications on flap complications compared with papaverine.

METHODS

All consecutive free flaps performed for breast reconstruction at a single institution were reviewed. Data collected included patient demographics, comorbidities, complications, and type of antispasmodic agent. Rates of reexploration, complications, and flap salvage were compared between patients receiving antispasmodic agents and matched papaverine controls.

RESULTS

Of the 1087 flaps treated with antispasmodic agents, nicardipine was used on 59 flaps and lidocaine was used on 55 flaps. Patients treated with lidocaine had higher body mass indexes (31.0 kg/m versus 27.4 kg/m; p = 0.001). Patients treated with nicardipine tended to be older (64.0 versus 48.5; p < 0.01) and have a history of hypertension (22.0 percent versus 10.4 percent; p = 0.08) or preoperative irradiation (32.2 percent versus 13.6 percent; p = 0.016) compared with papaverine controls. No differences in the rates of total or partial flap loss, unplanned return to the operating room, or fat necrosis were observed between any of the groups. However, the nicardipine group demonstrated a higher rate of infection (15.3 percent versus 3.4 percent; p = 0.027).

CONCLUSION

Substituting lidocaine or nicardipine for papaverine to treat vasospasm did not demonstrate an increased rate of flap loss or return to the operating room, making these medications safe and efficacious alternatives to papaverine.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Periarterial papaverine to treat renal artery vasospasm during robot-assisted laparoscopic partial nephrectomy

Renal artery vasospasm can be a troublesome complication during robot-assisted laparoscopic partial nephrectomy. Urologists performing this procedure, especially if utilizing selective arterial vascular microdissection, should be aware of using papaverine for both prevention and treatment of renal artery vasospasm. We present a 33-year-old male who developed severe renal artery vasospasm just with hilar dissection causing the kidney to become ischemic. Papaverine was topically applied on the renal arteries resulting in vasodilation and reperfusion of the kidney. Our objective of this report is to raise awareness of this complication as well as to review the literature on periarterial papaverine use and the dosing for topical applications.

Metamizole: an effective solution for vasospasm

OBJECTIVE

Vasospasm is a major problem during microsurgery, and a variety of pharmacological agents are used to alleviate vasospasm. This study aimed to demonstrate the effect of metamizole on vasospasm and to compare it with lidocaine and papaverine, both of which are commonly used to correct vasospasm.

METHODS

Thirty-five female rats were randomly divided into four groups: Group 1, 2, 3, and 4, which were the control (n = 8), metamizole (n = 9), papaverine (n = 9), and lidocaine (n = 9) treatment groups, respectively. Both femoral arteries of all of the rats were dissected, and they were immediately photographed. The pharmacological agents or saline in the control group were topically applied to the arteries, accordingly. The arteries were photographed again at time points 5, 10, 20 and 30 minutes after application of the agents. The images were transferred to a computer and the arteries' diameters were measured in mm.

RESULTS

All of the pharmacological treatments increased the diameter of the arteries significantly during the observation period. However, comparison between the groups indicated that metamizole and papaverine produced significantly more vasodilation than the lidocaine group, for all time points measured after application.

CONCLUSION

These findings show that topically applied metamizole is as effective as papaverine at alleviating vasospasm during the 30 minutes time interval. This administration may be considered as a good alternative to correct vasospasm during microsurgery.

Peripheral sympathectomy as a novel treatment option for distal digital necrosis following parenteral administration of promethazine

Promethazine is a commonly used medication to treat nausea and motion sickness. Case reports have recently surfaced on the dangers of parenteral administration of promethazine. We present a case report of a presumed intravenous injection of promethazine into an antecubital intravenous line resulting in necrosis of the ring finger distal to the DIP joint and hypoperfusion of the digits. Peripheral sympathectomy was performed to improve nutritional flow and improve ischemic pain. However, although this novel treatment option was successful, ultimately the patient had an amputation of her ring finger at the level of her middle phalanx. Although no proven successful treatment exists, the updated treatment options following inadvertent intra-arterial or perivascular administration are presented. Given the limited success of current treatment options for intra-arterial or perivascular extravasation, the staggering medical malpractice awards in such cases, and the numerous therapeutic alternatives to promethazine, the medical community should question the safety and continued administration of promethazine by an intravenous route.

Effect of sildenafil citrate on viability of flaps: an experimental study in rats

Various pharmacological agents have been used to try and elucidate the pathophysiology of ischaemia and necrosis of flaps. Their most important disadvantage is the need for relatively high doses given systemically, which increases the risk of potential side effects. Topical or local agents are more useful. Sildenafil citrate, the specific inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE 5) was studied as an antianginal drug during the late 1980s, but is now used for its effect on erectile function in men. Sildenafil citrate causes dilatation of peripheral arteries and veins and the inhibition of the thrombus-forming ability of platelets in vivo. Our study was designed to test the efficacy of sildenafil citrate on the viability of flaps.