Coronary artery spasm following coronary artery surgery

Refractory hypotension and coronary artery spasm induced by antipsychotic drugs: A challenging case and treatment consideration: A case report and literature review

RATIONALE

Coronary artery spasms may result from supply-demand mismatch due to hypotension. Norepinephrine is more effective in ameliorating antipsychotic-induced refractory hypotension.

PATIENT CONCERNS

Postoperative difficult-to-correct hypoperfusion occurs in patients with comorbid depression and coronary spasm; the use of norepinephrine and epinephrine for rapidly raising blood pressure needs to be considered.

DIAGNOSES

Electrocardiogram is an auxiliary tool and Digital Substraction Angiography is the gold standard for the diagnosis.

INTERVENTIONS

Surgery and correct choice of raising blood pressure are the main treatment methods.

OUTCOMES

Hypotension induced by the use of antipsychotics after angiography is difficult to correct with dobutamine, and the above scenario is relatively rare in the clinic, where norepinephrine could be a potential therapeutic option.

LESSONS

Based on the lessons learnt from this case, caution must be exercised when dealing with patients on multiple antipsychotics during the perioperative period, while pressor-boosting medications should not be limited to conventional drugs such as dopamine. Norepinephrine may be more effective in dealing with difficult-to-correct hypoperfusion.

Severe Coronary Artery Vasospasm after Mitral Valve Replacement in a Diabetic Patient with Previous Stent Implantation: A Case Report

Postoperative coronary vasospasm is a well-known cause of angina that may lead to myocardial infarction if not treated promptly. We report a case of a 70-year-old female with severe mitral regurgitation submitted to mitral valve replacement, and a history of diabetes mellitus type II, stroke, idiopathic thrombocytopenic purpura on steroid therapy, and previous percutaneous coronary intervention (PCI) for severe obstruction of the circumflex coronary artery, 4 months prior to surgery. Immediately after intensive care unit admission, the patient developed pulseless electrical activity which required extracorporeal membrane oxygenation for hemodynamic support. The coronary angiography showed diffuse occlusive coronary artery vasospasm, ameliorated after intra-coronary administration of nitroglycerin. The following postoperative evolution was marked by cardiogenic shock and multiple organ dysfunction syndrome. Subsequent echocardiographic findings showed an increase in left ventricular function with an EF of 40%, and extracorporeal membrane oxygenation (ECMO) support was weaned after seven days. However, after a few hours, the patient progressively deteriorated, with cardiac arrest and no response to resuscitation maneuvers. Hemodynamic instability following the surgical procedure in a patient with previous PCI associated with an autoimmune disease and diabetes mellitus should raise the suspicion of a coronary artery vasospasm.

Perioperative coronary artery spasm after off-pump coronary artery bypass grafting in the non-manipulated coronary artery

BACKGROUND

Perioperative coronary artery spasm (CAS) following coronary artery bypass grafting (CABG) is a severe or lethal condition that is rarely reported. In addition, rare cases with CAS following CABG in the non-manipulated coronary artery are angiographically documented in the perioperative period. We aimed to report our experiences on the diagnosis and treatment of a case with CAS following off-pump CABG in the non-manipulated coronary artery.

METHODS

A 57-year old male with coronary heart disease and unstable angina willing to undergo CABG was admitted to our department. CABG was recommended as he showed 90% stenosis in distal left anterior descending artery, 90% stenosis in intermediate branch, 90% stenosis in left circumflex coronary artery, as well as 50% stenosis in proximal right coronary artery (RCA).

RESULTS

After CABG, the patient showed Adams-Stokes syndrome and ST-segment elevation. Then CPR was conducted and coronary angiography indicated perioperative CAS in the non-manipulated posterior descending artery. For the treatment, the patient received nitroglycerin injection into the coronary artery by catheter and pumping of diltiazem. Finally, the patient was discharged on day 7 after surgery. A comprehensive literature search was conducted to summarize the studies focused on the diagnosis and treatment of such condition, which indicated that all of the CAS cases occurred in the manipulated vessels, except one study showing CAS in the untouched native coronary artery which was similar with our case.

CONCLUSIONS

Perioperative CAS in the non-manipulated coronary artery following CABG is a severe or lethal condition that is rarely reported, which deserves close attention by the clinicians in clinical practice.

Massive coronary spasm of the native coronary system after coronary artery bypass grafting: Two patients with different outcomes

We report the cases of two patients who developed a massive spasm of the native coronary system in the immediate postoperative period, following a coronary artery bypass grafting operation with different outcomes. The first patient was hemodynamic stable and it was manifested as ischemic electrocardiographic changes in different leads (ST elevation or depression). He was treated with intracoronary and intravenous administration of nitroglycerin and calcium channel blocker and had a favorable outcome. The second patient died due to multiorgan failure and hemorrhagic shock, after the implantation of a central venoarterial extracorporeal membrane oxygenation.

Late perioperative native coronary artery spasm following bypass grafting in a patient with anomalous aortic origin of the coronary artery

Native right coronary artery (RCA) spasm is a less frequent early complication of perioperative coronary artery bypass grafting. Late presentation at 6 days postoperation is scarce and its relationship with an anomalous coronary artery is unknown. The optimal management and prevention remains controversial. In the case presented, the patient's anomalous left coronary artery originating from the right coronary cusp underwent ligation at its proximal segment at the time of bypass grafting. This ligation was preformed to prevent competitive flow. Six days postoperation, a refractory spasm of dominant native RCA occurred. The spasm resulted in right ventricular failure. Administration of intracoronary verapamil had a longer sustained vasodilatory effect and resolution of coronary spasm when compared with intracoronary nitroglycerine injection. An intra-aortic balloon pump, inotropic agents and low-dose nitroglycerine were used to maintain adequate haemodynamic support. Right ventricular systolic function recovery was noted within 2 days postintervention.

Suspected Arterial Vasospasm in Femoro-Femoral Venoarterial Extracorporeal Life Support

Extracorporeal life support (ECLS) is increasingly used worldwide in patients with life-threatening hemodynamic or respiratory conditions. The femoral venoarterial cannulation, whether percutaneous or surgical, is the simplest and quickest method; however, a number of vascular complications may occur. We present two cases in which, despite a well-placed reperfusion cannula in the superior femoral artery, apparent limb ischemia of the cannulated limb developed rapidly after ECLS implantation and was suspected to be caused by arterial vasospasm. Both cases were successfully managed with the injection of a vasodilator cocktail of verapamil, nitroglycerin, and lidocaine directly in the reperfusion cannula.

A rare case of late onset saphenous vein graft spasm

Spasm following coronary artery bypass graft surgery has been well established in arterial grafts, especially in grafts utilizing the internal mammary. Venous graft spasms are uncommon and are only observed in vein grafts during or soon after the coronary artery bypass surgery. It is exceedingly rare to see spasm of venous graft beyond one year of surgery. We report a 72-year-old female who had coronary artery bypass graft three years ago and presented with new onset chest pain for one month. The coronary angiogram revealed severe spasm of the proximal aspect of a patent saphenous venous graft which was relieved by intracoronary nitroglycerine. Patient was successfully managed using combination of anti-spasmodic medications (nitrates and calcium channel blockers) leading to long-term resolution of her anginal symptoms.

Levels of vitamin C In the blood plasma patients treated with coronary artery bypass grafting increases significantly after surgery

One strong risk factor of coronary artery disease (CAD), which affects the levels of vitamin C in the blood is cigarette smoking. The supplementary effects of coronary artery bypass grafting (CABG) is smoking cessation by patients. Therefore, the aim of this study was to examine the level of vitamin C in the blood plasma one day before and one month after CABG. Human blood were collected from 20 patients (men); 1day before and 1 month after CABG. All patients were smoker and after CABG they declared their not smoking. The concentration of vitamin C in the blood plasma was assayed by FIA method with spectrophotometric detection. The mean value of the vitamin C concentration 1day before CABG was 12.36±2.84μmol/L (mean±SD), 1 month after CABG 40.07±10.95μmol/L (mean±SD). The average increase in the concentration of vitamin C was 3.27±0.73 times (mean±SD) and showed significant positive correlations (Pearson r=0.657, p=0.002). It should be consider incorporating the recommendations of preoperative smoking cessation for at least one month prior to CABG and/or additional supplementation. In addition it would be relevant to monitor the level of vitamin C in the patients' blood in the preoperative period.

Pharmacologic Management of Acute Heart Failure: A Review

Because of improved social and medical standards in the western world, the average age of the population continues to increase. This altering demographic profile has its impact on the surgical population, resulting in a dramatic increase in the number of patients with exten sive cardiovascular disease, presenting for either car diac or noncardiac surgery. As a result, the incidence of perioperative acute congestive heart failure (CHF) is a major clinical problem at the present time. For the pharmacologic management of acute CHF, the β-adreno ceptor agonists continue to be the mainstay of therapy, due to their short duration of action and hemodynamic controlability by continuous intravenous infusion. Mono therapy with the phosphodiesterase type III (PDE) inhibi tors appears to be the treatment of choice in selected patients with high systemic vascular resistance or re sidual β-adrenoceptor blockade. Combination therapy especially deserves attention, because this approach allows the enhancement of contractile force, possibly without the side effects associated with the administra tion of high concentrations of one agent alone. New developments including ultrashort-acting PDE inhibi tors, calcium-dependent calcium sensitizers, and cal cium promotors are anxiously awaited.

Effects of intraoperative diltiazem infusion on flow changes in arterial and venous grafts in coronary artery bypass graft surgery

Objective

This study aimed to show the effects of intra-operative diltiazem infusion on flow in arterial and venous grafts in coronary artery bypass graft surgery.

Methods

Hundred fourty patients with a total of 361 grafts [205 (57%) arterial and 156 (43%) venous] underwent isolated coronary surgery. All the grafts were measured by intraoperative transit time flow meter intra-operatively. Group A (n=70) consisted of patients who received diltiazem infusion (dose of 2.5 microgram/kg/min), and Group B (n=70) didn't receive diltiazem infusion.

Results

Mean graft flow values of left internal mammary artery were 53 ml/min in Group A and 40 ml/min in Group B (P<0.001). Pulsatility index (PI) values of left internal mammary artery for Group A and Group B were 2.6 and 3.0 respectively (P<0.001). No statistically significant difference was found between venous graft parameters.

Conclusion

We recommend an effect of diltiazem infusion in increasing graft flows in coronary artery bypass graft operations.

Potassium induced contraction of the internal thoracic artery in vitro is time related: the potential consequences in the analysis of the mechanism of the spasm after coronary artery bypass grafting and in the analysis of the results of in vitro studies

The aim of the present study was to examine how, under in vitro conditions, the human left internal thoracic artery (LITA) reacts to contractile agonist:potassium chloride (KCL) as a function of time, as well as to examine whether a change in the LITA reactivity can correlate with the occurrence of the refractory vascular spasm (RVS). Distal segments of LITA obtained from 33 patients aged 38–73, at the time of routine coronary artery surgical revascularization (CABG). Contractile response to 80 mmol K⁺ was recorded under isometric conditions. In 16 (48,5 %) LITA segments, contractile reaction to K⁺ after experiments ranging 1–10 h were registered. No contractile response even after 10 h of incubation was observed in 17 (51.5 %) LITA segments. Between 120 and 300 min after the beginning of the experiment, the reaction was maximum and amounted up to 300 % control reaction, then decreased. First, with respect to in vitro research isolated by LITA rings, while analyzing the results of the research, one should take into consideration the possibility that during the research, the functional state of the tissues changes and in particular its sensitivity to depolarization of the cell membrane. Second, the change in the sensitivity to depolarization of the cell membrane of the smooth muscles’ LITA might be the potential mechanism causing the occurrence of the postoperative spasm after the CABG treatment.

Rottlerin-induced BKCa channel activation impairs specific contractile responses and promotes vasodilation

BACKGROUND

Activation of large conductance calcium-activated potassium (BKCa) channels is cardioprotective for ischemic injury and can enhance vasorelaxation. Rottlerin has recently been identified as a potent BKCa activator. We demonstrated that rottlerin improves cardiac function and increases coronary flow when used as a cardioplegia additive in rat and mouse models of cardioplegic arrest and reperfusion. In this study we examined the effectiveness and specificity of the putative BKCa activator rottlerin on vascular reactivity in response to specific contractile and dilatory agonists.

METHODS

Aortic rings from wild-type (wt) and BKCa knock-out (KO) mice were mounted in a tissue bath with force transducers. The vasodilatory effect of rottlerin was evaluated after pre-constriction with U46619. Dose responses to the contractile agonists U46619 and phenylephrine (PE), and vasodilation responses to rottlerin, hydrogen sulfide (H2S), and sodium nitroprusside (SNP) were performed after pretreatment with rottlerin. Similar studies were performed in pig coronary vessels.

RESULTS

The BKCa KO mouse aortic rings exhibited spontaneous contraction and had greater contractile responses to U46619 and reduced vasodilation to SNP compared with wt mice. The wt and KO responses to phenylephrine were similar. Rottlerin dose dependently dilated wild-type vessels, but not in BKCa KO animals. Pretreatment with rottlerin caused depressed U46619 responses, but had no effect on PE, SNP, or H2S-mediated responses. However, pig coronary vessels pretreated with rottlerin exhibited reduced contractile responses and enhanced nitric oxide-dependent dilation.

CONCLUSIONS

Rottlerin directly causes vasodilation through BKCa channel dependent mechanisms. The BKCa channel activator pretreatment enhances vasodilatory responses and impairs specific vasoconstrictive agonists.

Vasoconstrictor responses to vasopressor agents in human pulmonary and radial arteries: an in vitro study

BACKGROUND

Vasopressor drugs, commonly used to treat systemic hypotension and maintain organ perfusion, may also induce regional vasoconstriction in specialized vascular beds such as the lung. An increase in pulmonary vascular tone may adversely affect patients with pulmonary hypertension or right heart failure. While sympathomimetics constrict pulmonary vessels, and vasopressin does not, a direct comparison between these drugs has not been made. This study investigated the effects of clinically used vasopressor agents on human isolated pulmonary and radial arteries.

METHODS

Isolated pulmonary and radial artery ring segments, mounted in organ baths, were used to study the contractile responses of each vasopressor agent. Concentration-response curves to norepinephrine, phenylephrine, metaraminol, and vasopressin were constructed.

RESULTS

The sympathomimetics norepinephrine, phenylephrine, and metaraminol caused concentration-dependent vasoconstriction in the radial (pEC50: 6.99 ± 0.06, 6.14 ± 0.09, and 5.56 ± 0.07, respectively, n = 4 to 5) and pulmonary arteries (pEC50: 6.86 ± 0.11, 5.94 ± 0.05 and 5.56 ± 0.09, respectively, n = 3 to 4). Vasopressin was a potent vasoconstrictor of the radial artery (pEC50 9.13 ± 0.20, n = 3), whereas in the pulmonary artery, it had no significant effect.

CONCLUSIONS

Sympathomimetic-based vasopressor agents constrict both human radial and pulmonary arteries with similar potency in each. In contrast, vasopressin, although a potent vasoconstrictor of radial vessels, had no effect on pulmonary vascular tone. These findings provide some support for the use of vasopressin in patients with pulmonary hypertension.

Refractory vascular spasm associated with coronary bypass grafting

Diffuse refractory vascular spasms associated with coronary bypass artery grafting (CABG) are rare but devastating. A 42-year-old male patient with a past history of stent insertion was referred for the surgical treatment of a recurrent left main coronary artery disease. A hemodynamic derangement developed during graft harvesting, necessitating a hurried initiation of cardiopulmonary bypass (CPB). Although CABG was carried out as planned, the patient could not be weaned from the bypass. An emergency coronary angiography demonstrated a diffuse spasm of both native coronary arteries and grafts. CPB was switched to the femorofemoral extracorporeal membrane oxygenator (ECMO). Although he managed to recover from heart failure, his discharge was delayed due to the ischemic injury of the lower limb secondary to cannulation for ECMO. We reviewed the case and literature, placing emphasis on the predisposing factors and appropriate management.

Coronary artery spasm following off-pump coronary artery bypass surgery

Coronary artery spasm after coronary artery bypass surgery may result in life-threatening arrhythmias, circulatory collapse, or death. We report two cases of coronary artery spasm after coronary artery bypass surgery, one of which developed ventricular fibrillation requiring extracorporeal membrane oxygenation support. Both patients were discharged in good condition and are currently followed as outpatients. Unexpected sudden hemodynamic compromise could be due to coronary vasospasm, and this should be considered as one of the possible differential diagnoses. We were able to prevent the lethal consequences seen with coronary artery spasm by early diagnosis and management.

Intraoperative coronary artery spasm after off-pump coronary surgery

Coronary artery spasm is rare after coronary artery bypass surgery. We describe a case of intraoperative severe native coronary artery and graft spasm after successful off-pump coronary bypass surgery in a 55-year-old man, which was detected by suspicious electrocardiographic changes, and documented postoperatively by coronary angiography.

Native coronary artery and grafted artery spasm just after coronary artery bypass grafting: a case report

Native coronary artery spasm after coronary artery bypass grafting (CABG) is scarce. It frequently causes disastrous circulatory collapse. We report a 72-yr-old male, who experienced native coronary artery spasm and grafted artery spasm following CABG, which was successfully treated with coronary angiography and intracoronary injection of nitroglycerine.

Coronary artery spasm of the native right coronary artery during off-pump coronary surgery of the left coronary artery system

Native coronary artery spasm is a very rare complication during off-pump coronary artery bypass grafting. We report the case of a 74-year-old man who experienced angiographically documentated right coronary artery spasm while undergoing off-pump coronary artery bypass grafting on the diseased left coronary system. Despite two episodes of ventricular fibrillation and persistent ST segment elevation of the posterior wall, the off-pump procedure was successfully completed by grafting the left internal thoracic artery to the left anterior descending artery and a saphenous vein graft to the Ramus intermedius. The immediate postoperatively performed coronary angiography demonstrated patent anastomoses and two areas of significant spasticity within the course of the right coronary artery. Intracoronary nitroglycerin infusion into the ostium of the right coronary artery resolved the spasms of this nondiseased vessel as well as the associated ST segment elevations.

Hemodynamic management of patients in the first 24 hours after cardiac surgery

OBJECTIVE

To describe the physiologic alterations, evaluation, and hemodynamic management of patients in the first 24 hrs after cardiac surgery.

DESIGN

A brief review of preoperative and intraoperative events, postoperative physiology, and a discussion of the evaluation and hemodynamic management of cardiac surgery patients postoperatively based on a review of the literature, known physiology, and clinical experience.

RESULTS

After cardiac surgery, patients undergo alterations in cardiac performance related to co-morbid conditions, preoperative myocardial insults and interventions, the surgical procedure, and intraoperative management. Predictable responses evolve rapidly in the first 24 hrs after surgery. Monitoring, diagnostic regimens, and therapeutic regimens exist to address the patterns of response and occasional complications.

CONCLUSION

By understanding preoperative and intraoperative events and their evolution in the intensive care unit, clinicians can effectively manage patients who experience cardiac surgery.

Temporary left ventricular assist and levosimendan for coronary artery spasm

Coronary vasospasm is a life threatening complication in the early postoperative period after coronary artery bypass grafting. We report a 45-year-old patient with normal preoperative ventricular function who could not be stabilized using established treatments such as: systemic application of glyceryl trinitrate, diltiazem and milrinone, intraaortic balloon pumping and intracoronary injection of glyceryl trinitrate. Severe stunning of the myocardium required support with a centrifugal left ventricular assist device. Subsequent application of levosimendan, a calcium sensitizer, may have contributed to prevent recurrence of repeated episodes of coronary spasm, enabling early explantation of the assist device and a full recovery.

Coronary artery and graft spasm after off-pump coronary artery bypass grafting

We report a case of a 52-year-old man with severe coronary artery and graft spasm after triple-vessel off-pump coronary artery bypass grafting. Emergent coronary angiography was performed to identify the location and severity of the spasm. Intracoronary injections of several vasodilators failed to relieve the spasm. Observational treatments including intra-aortic balloon pump and inotropic drugs to increase coronary flow were performed until the spasm resolved. The patient recovered and was discharged. A follow-up coronary angiography revealed patent native coronary artery and bypass grafts without evidence of residual spasm.

L-arginine polymers enhance coronary flow and reduce oxidative stress following cardiac transplantation in rats

BACKGROUND

Hearts treated with l-arginine polymers have demonstrated upregulated production of nitric oxide. The current study examined whether these polymers improved coronary flow and reduced myocardial oxidative stress after rat heart transplantation.

METHODS

PVG donor hearts were incubated ex vivo with either 100 mumol/L l-arginine polymers 9 amino acids in length (R9) (n = 7) or phosphate-buffered saline (n = 7) for 30 minutes after arrest and then transplanted heterotopically into the abdomen of ACI recipient rats. Coronary flows were assessed using fluorescent microspheres both at baseline (30 minutes after reperfusion) and at 6 hours and compared using the paired Student t test. Evidence of oxidative stress was assessed in a separate cohort of similarly treated animals by enzyme-linked imunosorbent assay for rat tumor necrosis factor-alpha at 6 hours.

RESULTS

Histochemistry with biotinylated l-arginine polymers demonstrated uptake of R9 into the vascular walls of treated allografts. Although all hearts experienced deterioration in coronary flow between baseline and 6 hours, the R9-treated group had a smaller reduction (29.9%, P =.10) than the phosphate-buffered saline control group (58.0%, P =.003). Tumor necrosis factor-alpha levels were also significantly reduced in the R9 treatment group compared with the phosphate-buffered saline category (160 +/- 30 versus 205 +/- 38, P =.007).

CONCLUSION

Rat cardiac allografts treated with R9 at the time of procurement exhibited less deterioration in coronary flow and a reduction in myocardial oxidative stress than the phosphate-buffered saline control group in the perioperative period. The use of arginine polymers may thus provide important myocardial protection against ischemia-reperfusion injury in both transplant and routine cardiac surgery cases.

Coronary artery spasm and ventricular fibrillation after off-pump coronary surgery

Native coronary artery or bypass graft spasm is a rare cause of acute myocardial infarction after coronary artery bypass grafting. This report presents angiographic documentation of native coronary artery spasm following successful multivessel off-pump coronary revascularization, which caused myocardial ischemia leading to inferior wall myocardial infarction and ventricular fibrillatory arrest.

Cardiopulmonary Complications Following Cardiac Surgery

There are numerous cardiac and pulmonary complications that can occur after operations that involve the use of cardiopulmonary bypass (CPB). We have chosen to focus on perioperative myocardial ischemia, left ventricular (LV) dysfunction, ventricular arrhythmias, atrial arrhythmias, and inflammation and pulmonary dysfunction as the most important. If left untreated, these complications can be life-threatening. Moreover, their presence is associated with higher hospital expenses due to therapies and longer inpatient stays.

Lethal postoperative coronary artery spasm

BACKGROUND

Coronary artery spasm in the immediate postoperative period after a coronary operation is recognized infrequently. Its severity is variable and manifestations unpredictable. The diagnosis is usually made by an awareness of the possibility and thereafter by exclusion of other causes of myocardial ischemia. An opportunity for a positive diagnosis is rarely available.

METHODS

The case reports of 3 patients with similar presentations of ischemic heart disease and with severe manifestations of coronary artery spasm in the postoperative period are presented.

RESULTS

All 3 patients were women aged 55 to 60 years. All had single-vessel coronary artery disease involving the left anterior descending artery and underwent a left internal mammary artery bypass graft. Severe manifestations of myocardial ischemia of abrupt onset developed approximately 7 hours postoperatively in each patient. One patient died of severe hemodynamic deterioration from which resuscitation was unsuccessful. Another sustained a large anterior myocardial infarction despite graft patency. The third patient was supported by an intraaortic balloon pump and made a full recovery.

CONCLUSIONS

The early diagnosis of coronary artery spasm is achieved by an awareness of the condition. The institution of early appropriate management may prevent its consequences.

Mitogen-activated protein kinase activation: an alternate signaling pathway for sustained vascular smooth muscle contraction

PURPOSE

The vascular smooth muscle determines the dynamic caliber of the blood vessel and hence is the final effector cell in modulating vasomotor tone. Although considerable information is available regarding the physiologic agonists that induce contraction, less is known about the cellular signaling events that lead to long-lasting contractions or vasospasm. We examined the hypothesis that activation of mitogen-activated protein (MAP) kinase may be associated with sustained smooth muscle contractions.

METHODS

Physiologic contractile responses were determined in intact bovine carotid artery smooth muscles in a muscle bath. Corresponding signaling events were determined with immunoblots using antiphosphotyrosine antibodies or immunoprecipitation of whole-cell phosphorylated strips of muscle.

RESULTS

The tyrosine kinase inhibitor, genestein, significantly inhibited the magnitude of contractions induced by phorbol ester, endothelin, angiotensin, and serotonin. In addition, genestein inhibited the sustained phase of contractions induced by serotonin. Serotonin-induced vascular smooth muscle contractions were temporally associated with an increase in the phosphorylation of MAP kinase.

CONCLUSIONS

These data suggest that the activation of MAP kinase is associated with sustained vascular smooth muscle contractions. Pharmacologic manipulation of MAP kinase activation may lead to new approaches to treat pathologic circumstances of increased vasomotor tone such as vasospasm.

Papaverive abolishes endothelium-dependent dilatation of human internal mammary arteries in vitro

1. The purpose of the present study was to examine the effects of papaverine-HCl, administered into the lumen of the human internal mammary artery (IMA) during harvesting of this vessel, on vascular reactivity in vitro and to specifically test the hypothesis that intraluminal administration of papaverine-HCl impairs endothelium-dependent vasodilation. 2. The present study measured in vitro dilator and constrictor responses of terminal segments of human IMA. Internal mammary artery segments were obtained either prior to routine administration of intraluminal papaverine (pre-P) or after papaverine administration (post-P) in patients undergoing coronary artery bypass grafting. In addition, the viability of cultured human saphenous vein endothelial cells exposed to papaverine-HCl was examined. 3. Cumulative concentrations of U46619, 5-hydroxytryptamine and phenylephrine (PE) produced active contractions in post-P IMA rings. Contractile responses to low concentrations of endothelin-1 were significantly enhanced in post-PIMA compared with pre-P IMA segments. 4. Maximal endothelium-dependent vasodilator responses of pre-P IMA segments to cumulative concentrations of acetylcholine (ACh) and the calcium ionophore A23187 were 49 +/- 7 and 66 +/- 4%, respectively, of the initial active tension induced by PE (1 mumol/L). 5. Maximal endothelium-dependent vasodilator responses were markedly attenuated in post-P IMA (6 +/- 6 and 11 +/- 10% for ACh and A23187, respectively; P < 0.0001 for both vasodilators compared with pre-P). Post-P IMA relaxed completely to the endothelium-independent vasodilator sodium nitroprusside. 6. Exposure of cultured human saphenous vein endothelial cells to papaverine-HCl (1.2 and 12.0 mg/mL) for 1 h resulted in the reduced viability of these cells. 7. The loss of endothelium-dependent relaxation could dangerously predispose the IMA graft to vasospasm in the postoperative period.

Endothelial cell injury in cardiovascular surgery: the pathophysiology of vasomotor dysfunction

Impaired vasomotor function has been suggested as playing a role in the pathophysiology of hypertension, diabetes, hypercholesterolemia, and atherosclerosis, all of which are common in cardiovascular surgery patients. In addition to chronic vasomotor dysfunction, alterations in vasomotor tone can result in acute arterial spasm, microcirculatory ischemia, and wide variations in systemic blood pressure. Changes in the health of the vascular endothelium may also impact the late patency of coronary artery bypass grafts, the progression of atherosclerosis in the native coronary circulation, and the long-term success of cardiac transplants. In the resting state the endothelium produces several substances that promote vascular relaxation and inhibition of platelet function, thus assuring the unhindered flow of blood through the capillaries. In response to injury, the endothelium loses some capacity to relax and also releases powerful vasoconstrictive agents. Attempting to understand the contributions that these substances play in the vasomotor dysfunction seen after cardiothoracic surgery is an area of active investigation.

Immediate postoperative care of cardiac surgical patients

Anesthetic care of the cardiac surgery patient is a continuum, beginning with the preoperative visit and ending when the patient is ambulatory and breathing well on the postoperative floor. Anesthesiologists are well-suited to provide postoperative care because the respiratory and cardiovascular management techniques are an extension of OR management. Attention to details is as important in the ICU as in the OR and offers the opportunity to forestall or reduce morbidity.

Myocardial injury during reoperation for coronary artery bypass surgery

OBJECTIVES

To determine the incidence, triggers, and timing of myocardial injury during reoperation for coronary artery bypass surgery.

DESIGN

Prospective observational.

SETTING

One tertiary care university hospital.

PARTICIPANTS

15 patients undergoing reoperation.

INTERVENTIONS

Multilead electrocardiographic monitoring approximately every 3 minutes during surgery.

MEASUREMENTS AND MAIN RESULTS

The occurrence of a new ischemic ST elevation or depression on the electrocardiogram (ECG) was determined. A major deterioration in ventricular function after cardiopulmonary bypass (CPB) also was determined. Peak creatine kinase myocardial band (CK-MB) > or = 25 IU/L was considered to be the marker of myocardial injury. Seven patients demonstrated myocardial injury, all intraoperatively. Five of these patients had new ST elevation episodes before CPB. Three of the episodes were temporally associated with an abrupt increase in the heart rate. The other two episodes were temporally associated with surgical manipulation of the heart and the old grafts. The sixth patient had a significant deterioration of ventricular function during CPB. One of the patients who had ST elevation before CPB and the seventh patient developed ST elevation towards the end of protamine administration.

CONCLUSIONS

In patients undergoing reoperation, the intraoperative incidence of myocardial injury, especially before CPB, was found to be substantially higher than that previously reported.

Myocardial ischemia after cardiopulmonary bypass

Intraoperatively, myocardial ischemia is more common after cardiopulmonary bypass (CPB) than before CPB. Ischemia associated with coronary vasospasm and thrombosis may be much more common toward the end of surgery and early in the postoperative period than previously appreciated. This may be because the coagulation system is altered during CPB, and the coronary endothelium is damaged significantly as a result of cardioplegic arrest followed by reperfusion. In this milieu, vasospasm and thrombosis may be caused by the administration of protamine. Some of the ischemia observed in this period actually is not reversible and is associated with myocardial injury and infarction. It may be ameliorated by the administration of calcium channel blockers, aspirin, and anticoagulants. Electrocardiography may be the most suitable modality for the detection of ischemia after CPB and postoperatively. During this period, many episodes of ST deviation are of a nonischemic etiology, and the ECG needs careful interpretation. Transesophageal echocardiography is suitable for use intraoperatively and early on in the intensive care unit.

Calcium administration for cardiovascular support in critically ill patients: when is it indicated?

Calcium has a fundamental role in the maintenance of myocardial function and vascular tone. The ionized form of calcium is the most important physiologically, and this form needs to be measured to assess physiologically active calcium levels. Ionized hypocalcemia can occur as a result of various pathophysiological disturbances, and it is seen frequently in critically ill patients. Several investigators have observed a poorer prognosis in those patients with ionized hypocalcemia. It is unclear whether calcium supplementation is beneficial in these patients. It may improve cardiovascular performance, but, in contrast, it may contribute to cellular damage (especially during hypoxia following cardiopulmonary resuscitation). In sepsis, there may be an increased cellular influx of calcium, which may be deleterious to cellular function; indeed, calcium entry blockers in this situation may be protective. We review the role of calcium as an inotropic agent, its interaction with other inotropic agents, and its use during blood transfusion and during cardiopulmonary resuscitation.

Influence of intravenous calcium gluconate on saphenous vein graft flow in closed-chest patients

The effects of calcium gluconate on hemodynamics and saphenous vein graft flow in a group of patients undergoing elective coronary artery bypass grafting who developed ionized hypocalcemia at the end of the surgical procedure were examined. The patients received a central venous bolus of 15 mg/kg of calcium gluconate. Heart rate (HR), arterial pressure (AP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output were measured immediately before and 30, 60, 120, 180, and 240 seconds after injection of calcium gluconate. Systemic and pulmonary vascular resistance (SVR and PVR, respectively), cardiac index (CI), stroke volume index (SVI), and right and left ventricular stroke work index (RVSWI and LVSWI, respectively), were calculated. Venous bypass flow velocity (Vbypass-flow) was assessed using a Doppler probe that was attached to the left anterior descending artery (LAD) bypass intraoperatively. Calcium gluconate significantly increased MAP, SVR, and LVSWI from 67 +/- 3 mmHg (mean +/- SEM), 1,128 +/- 128 dyne.s.cm-5 and 25 +/- 3 g.m.beat/m to a maximum of 81 +/- 5 mmHg (P < 0.01), 1,401 +/- 196 dyne.s.cm-5 (P < 0.05), and 32 +/- 4 g.m/beat/m (P < 0.01), respectively. HR, CVP, PAP, PCWP, PVR, CI, SVI, and Vbypass-flow remained unaltered. It is concluded that calcium gluconate administered to moderately hypocalcemic patients increases arterial pressure mainly by peripheral vasoconstriction. Because the increase of arterial pressure, and, thereby, coronary perfusion pressure is not associated with an increase of LAD bypass flow, vasoconstriction in the coronary vascular bed distal to the venous graft cannot be ruled out, and deterioration of the myocardial oxygen supply/demand ratio is strongly suggested.

Determinants of low systemic vascular resistance during cardiopulmonary bypass

Although low systemic vascular resistance occurs during normothermic and hypothermic cardiopulmonary bypass, the determinants of depressed systemic vascular resistance and its effect on outcomes are unknown. To assess the predictors and clinical effects of low systemic vascular resistance, 555 patients undergoing isolated coronary artery bypass grafting were evaluated prospectively. The extent of low systemic vascular resistance during bypass was estimated by the amount of the vasoconstrictor phenylephrine administered: group 1, 0 to 160 micrograms; group 2, 161 to 800 micrograms; group 3, more than 800 micrograms. Multivariate analysis identified bypass temperature, bypass time, and ventricular function as determinants of low systemic vascular resistance. Patients on normothermic bypass accounted for 65% of the patients in group 3 and only 34% of the patients in group 1 (p < 0.0001). The bypass time was longer in the patients in group 3 (97 +/- 28 minutes) than in the patients in group 1 (89 +/- 24 minutes; p < 0.006). Patients with a preoperative left ventricular ejection fraction of 0.40 or less required less phenylephrine during cardiopulmonary bypass (498 +/- 68 micrograms) than did patients with a fraction exceeding 0.40 (1,087 +/- 88 micrograms; p < 0.001). By multivariate analysis, advanced age and the presence of peripheral vascular disease were found to decrease the likelihood of low systemic vascular resistance during normothermic bypass. Diabetes, the left ventricular ejection fraction, the bypass time, and the total cardioplegia infused were found to influence the likelihood of low systemic vascular resistance during hypothermic bypass. Patients in group 3 had a higher cardiac index and lower-mean arterial pressure and systemic vascular resistance postoperatively. In those patients who received a left internal mammary artery graft, the incidences of the low-output syndrome (group 1, 4.9%; group 3, 2.7%; p = not significant) and myocardial infarction (group 1, 1.4%; group 3, 1.8%; p = not significant) were not influenced by the amount of phenylephrine infused during cardiopulmonary bypass. In those patients who were at high risk of suffering a stroke preoperatively, the hypotension induced by the low systemic vascular resistance and its treatment with phenylephrine was not associated with an increased incidence of stroke (group 1, 5.8%; group 3, 2.8%; p = not significant).

Coronary artery spasm after aortic valve replacement

We report a patient who received aortic valve replacement and experienced early postoperative coronary artery spasm, which led to inferolateral myocardial infarction. The spasm was unresponsive to conventional medication. However, after systemic circulatory and respiratory control, a good prognosis was obtained.