Preparation of the internal thoracic artery by vasodilator drugs: is it really necessary? A randomized double-blind placebo-controlled clinical study

Use of nitroglycerin and verapamil solution by organ bath technique in preparation of left internal thoracic artery for coronary artery bypass surgery

Background

The aim of this prospective study was to compare the effect of application of nitroglycerin and verapamil solution (GV) by organ bath technique with other methods of applications and solutions on the free blood flow of LITA. The technique was not described for in situ graft before.

Method

The patients were randomly assigned to four groups: group I (n_32, GV solution by organ bath technique), group II (n_30, papaverine solution by organ bath technique), group III (n_29, topical GV solution) or group IV (n_29, topical papaverine solution). In each patient, pedicled LITA was harvested; thereafter applied with the randomized different methods and solutions. The free flow from the distal end of the divided LITA was measured for 15 s under controlled hemodynamic conditions after harvesting (Flow 1). The flow of LITA was measured again just prior to anastomosing the conduit (Flow 2).

Result

The mean blood flow in LITA was 56.2 ± 5.0 ml/min before application of solutions. After application, the mean blood flow in group I:102.3 ± 7.0 ml/min, in group II: 92.7 ± 3.4 ml/min, and in group III: 88.6 ± 2.2 ml/min and in group IV: 81.4 ± 2.1. Proportional increases in blood flow observed in group I (82.6%) > group II (65.1%) > group III (57.6) > group IV (44.8%) (p < 0.05).

Conclusions

GV solution by organ bath technique is effective and superior in comparison to use of papaverine using organ bath technique or topical spray of GV or papaverine solution.

Fasudil Is an Effective Graft Vasodilator for Gastroepiploic Artery in Coronary Artery Bypass Grafting

OBJECTIVE

The gastroepiploic artery (GEA) has been used as an alternative arterial in situ graft for coronary artery bypass grafting (CABG). However, because of the large individual differences and the spastic nature of the GEA, caution has to be exercised during harvesting. We evaluated the usefulness of fasudil, a Rho kinase inhibitor, as a vasodilator for right GEA (RGEA) graft after harvesting, compared with the conventional agents papaverine and verapamil-nitroglycerin.

METHODS

Between June 2009 and January 2013, 30 patients with ischemic heart disease who underwent isolated CABG using RGEA graft were randomly assigned to fasudil (n = 10), papaverine (n = 10), or verapamil-nitroglycerin (n = 10) group. Fasudil (2.67 mmol/L), papaverine (1.0 mmol/L) mixed with heparinized blood, or verapamil-nitroglycerin (30 μmol/L each) was injected intraluminally into the RGEA graft after harvesting. Right GEA graft free flow (GFF), hemodynamic changes, and histopathology of RGEA were evaluated.

RESULTS

Intraluminal injection of fasudil increased GFF significantly (P < 0.001) and markedly from 41.5 ± 31.5 mL/min at baseline to 149.3 ± 46.7 mL/min after injection. Papaverine increased GFF (P < 0.001) from 40.0 ± 35.8 to 64.9 ± 33.7 mL/min, and verapamil-nitroglycerin also increased GFF (P < 0.001) from 38.8 ± 32.1 to 79.0 ± 35.2 mL/min. The GFF was significantly higher (P = 0.001) in the fasudil group than in the other two groups. Histopathologically, fasudil treatment markedly increased the diameter of RGEA graft, while maintaining integrity of the multiple elastic lamellae. Blood pressure did not change significantly after drug injection in all groups.

CONCLUSIONS

Fasudil is more potent than papaverine or verapamil-nitroglycerin in increasing GFF of RGEA graft for CABG.

Potent vasodilatory effect of fasudil on radial artery graft in coronary artery bypass operations

BACKGROUND

The radial artery (RA) is a useful conduit for coronary artery bypass grafting (CABG) but is susceptible to vasospasm during harvesting. We evaluated the usefulness of fasudil, a Rho kinase inhibitor, in dilating the RA graft and increasing graft free flow (GFF) compared with the conventional graft-dilating agents papaverine and verapamil-nitroglycerin (VG).

METHODS

Between June 2012 and January 2013, 45 patients with ischemic heart disease who underwent isolated CABG using the RA were enrolled and randomly assigned to fasudil (n = 15), papaverine (n = 15), or VG (n = 15). Fasudil (2.67 mmol/L), papaverine (1.0 mmol/L) mixed with heparinized blood, or VG (30 μmol/L each of verapamil and nitroglycerin) was injected intraluminally into the RA graft after harvesting. Main outcome measures were RA GFF, hemodynamic changes, and histopathologic examination of the RA.

RESULTS

In the fasudil group, GFF increased significantly (p < 0.001) from 36.8 ± 20.4 at baseline to 148.0 ± 88.3 mL/min after injection. GFF increased significantly (p < 0.001) from 36.0 ± 19.0 to 72.3 ± 36.7 mL/min in the papaverine group and increased significantly (p < 0.001) from 39.5 ± 23.3 to 64.3 ± 29.9 mL/min in the VG group. The GFF was significantly higher (p = 0.001) in fasudil-treated RA than in papaverine- or VG-treated RA. Histopathologically, RA graft diameter was markedly increased after fasudil injection, and the structure of the multiple elastic lamellae was intact. Blood pressure did not change significantly after drug injection in all groups.

CONCLUSIONS

Fasudil exhibited a very potent vasodilatory effect on the RA compared with conventional papaverine or VG, resulting in increased GFF. This agent is useful for dilating RA grafts in CABG.

Pharmacokinetics of Intraluminally Administered Serum Papaverine for Spasm Prophylaxis of the Internal Mammary Artery

Background: Papaverine (Paveron N™ Linden Arzneimittel Vertrieb GmbH, Germany) is a widely used agent for preventing spasm in mammary artery preparations. The question addressed in this study is whether the intraluminal administration of papaverine can result in detectable absorption of the drug into the systemic arterial circulation.Methods: In 15 patients (age 65 ± 6 years; body mass index 28.9 ± 3.7), an internal mammary artery (IMA) was prepared during coronary artery bypass grafting (CABG). A maximum of 3 mL of a 1 mg/1 mL diluted papaverine solution was injected intravascularly (intraluminally) for spasm prophylaxis. The IMA was closed proximally and distally with bulldog clamps. Blood samples were taken immediately after administration (T1), after 20 minutes (T2), and at the end of the operation (T3). Samples were measured in a liquid chromatography--tandem mass spectrometry (LC-MS/MS) system consisting of a binary pump from Agilent (Waldbronn, Germany) coupled to a high-throughput screening (HTS) PAL injection system (CTC, Zwingen, Switzerland) and a tandem mass spectrometer (API 4000, AB Sciex, Darmstadt, Germany). Papaverine was analyzed in positive mode using an electrospray ion source. Quantitation was performed using Analyst 1.5 software (AB Sciex, Darmstadt, Germany).Results: The newly developed LC-MS/MS method was successfully established for the detection of papaverine in plasma samples. The highest plasma papaverine levels were determined at time point T1 (mean 54.7 ± 39 ng/mL, range 16.6-179 ng/mL). The concentration was already halved 20 minutes after administration (T2) (mean 23.3 ± 2 ng/mL, range 4.6-118 ng/mL). Because of the short half-life and the hemodilution in the extracorporeal circulation, at the end of the operation papaverine (T3) had already fallen to just above the limit of detection (mean 4.1 ± 3.9 ng/mL, range 1.3-16.9 ng/mL). At time point T1, a significant negative correlation was determined between plasma levels and systemic diastolic, but not systolic, blood pressure.Conclusion: Papaverine was successfully determined systemically in plasma by LC-MS/MS after intraluminal administration in the IMA. Systemic circulatory effects are dependent on the detected quantity. Group size and the absence of a control group are considerable limitations.

Fasudil is a superior vasodilator for the internal thoracic artery in coronary surgery

BACKGROUND

The internal thoracic artery (ITA) is a very useful conduit for coronary artery bypass artery (CABG), with excellent long-term patency. With the purpose to dilate the ITA graft and increase graft free flow (GFF) intraoperatively, we evaluated the usefulness of intraluminal injection of fasudil, a Rho-kinase inhibitor, in comparison to the conventional graft dilating agent, papaverine.

METHODS

Between June 2011 and January 2012, 30 patients with ischemic heart disease who underwent isolated CABG using ITA were enrolled. The patients were randomly assigned to 2 groups: the fasudil group (n = 15) in which fasudil solution 0.9 mg/dL was injected into the ITA, and the papaverine group (n = 15) in which papaverine solution (0.4 mg/mL) mixed with heparinized blood was used. Outcome measures were left ITA GFF, heart rate, and mean blood pressure during flow measurements, and histopathologic examination of the ITA.

RESULTS

In the fasudil group, GFF increased significantly (p < 0.01) from 19.7 ± 15.2 mL/minute at baseline to 66.9 ± 31.7 mL/minute after fasudil injection. In the papaverine group, GFF increased significantly (p < 0.01) from 22.9 ± 17.3 mL/minute at baseline to 44.8 ± 26.7 mL/minute after papaverine injection. Blood pressure and heart rate did not change significantly after drug injection in both groups. The GFF was significantly higher (p = 0.038) in fasudil-treated ITA than in papaverine-treated ITA. Histopathologically, the diameter of the ITA was markedly increased after fasudil injection. Elastica van Gieson staining showed that the multiple elastic lamellae structure was intact.

CONCLUSIONS

Fasudil exhibited very potent vasodilatory effect on the ITA compared with conventional papaverine resulting in increased GFF. This agent is a useful graft dilating agent.

Effects of Pretreatment with Different Topical Vasodilators on Blood Flow in the Internal Mammary Artery: A Prospective Randomized Study

BACKGROUND

This study was conducted to investigate how brief pretreatments with 4 different vasodilators applied topically at normal body temperature affect blood flow in the internal mammary artery.

METHODS

One hundred patients who had an internal mammary artery mobilized as a pedicle for coronary artery bypass grafting were randomly assigned to one of 5 groups of equal size (20 subjects in each). Each group of pedicles was treated with a different topical solution: normal saline (control), nitroglycerin, diltiazem, papaverine, or adenosine. Internal mammary artery flow and hemodynamic measurements were recorded immediately after harvesting and after 5 minutes of immersion in a tube filled with test solution (50 mL at 37 degrees C). Results for each study variable were compared within and between groups, and posttreatment-to-pretreatment ratios were also calculated and compared.

RESULTS

All 4 vasodilator groups showed a significant increase in internal mammary artery flow rate from pretreatment to posttreatment, whereas the saline group did not. There were no significant differences among the 5 groups' pretreatment flow rates (P = .526) or posttreatment flow rates (P = .194). The mean ratio values (posttreatment-to-pretreatment) for flow rate were 1.08 +/- 0.17 in the saline group, 1.74 +/- 0.17 with nitroglycerin, 1.77 +/- 0.49 with diltiazem, 1.82 +/- 0.59 with papaverine, and 1.57 +/- 0.54 with adenosine. Post hoc analysis revealed that the mean ratio values for flow rate in the 4 vasodilator groups were significantly higher than the corresponding ratio in the saline group.

CONCLUSIONS

Brief treatment of the internal mammary artery with topical vasodilators at normal body temperature significantly increases blood flow in this vessel. The data from this study are particularly valuable in relation to off-pump surgery, in which this vessel is usually anastomosed soon after it is harvested.

An alternative application of sodium nitroprusside to overcome perioperative spasm of the internal thoracic artery

OBJECTIVE

The internal thoracic artery (ITA) is currently the preferred conduit for myocardial revascularization; however, perioperative vasospasm of the internal thoracic artery may cause morbidity. Pedicle preparation and pharmacological vasodilatory treatment vary greatly. This clinical study was performed in order to define the effectiveness of two different applications of sodium nitroprusside as vasodilating agent.

METHODS

Eighty-six (86) consecutive patients whose left internal thoracic artery was mobilized only by one surgeon for elective coronary artery bypass graft operations were randomly divided into two groups. The internal thoracic artery was allowed to bleed freely, and the flow was determined (flow 1). In group I (n=42) 3mg sodium nitroprusside in 10ml of 5% dextrose solution was sprayed with pressure on the pedicle with a thin 25 gauge needle. In group II (n=44) half of the solution was sprayed in the same manner, and the other half of the solution was injected into the pedicle in the periarterial tissue along the length of the pedicle. Free flows of the internal thoracic artery were registered before cardiopulmonary bypass (flow 2) and also just prior to performing internal thoracic artery anastomosis to the left anterior descending artery (flow 3). With each measurement hemodynamic parameters and the time between measurements were recorded.

RESULTS

No statistically significant differences were found between the groups in respect to sex ratio, age, body surface area, heart rate 1 and 2, mean arterial pressure 1 and 3. There was no significant difference in the initial flow among groups. Significant differences were noted in the second flow measurement (P<0.05) and in the third flow measurement (P<0.01) between two groups. For each group there was a significant increase in flow from flow 1 to flow 2 and from flow 2 to flow 3 (P<0.02).

CONCLUSION

Sodium nitroprusside injection to the pedicle provides a better flow than simple spraying of the same agent.