Hemodynamic and hormonal changes in patients pretreated with captopril for surgery of the abdominal aorta

ARNI Pre-Operative Use and Vasoplegic Syndrome in Patients Undergoing Heart Transplantation or Left Ventricular Assist Device Surgery

Background: Vasoplegic syndrome after orthotopic heart transplantation (OHT) or left ventricular assist device (LVAD) implantation is a rare but highly lethal syndrome with complex etiologies. The objective of this study was to assess if the preoperative use of sacubitril-valsartan combination is associated with an increased vasoplegic syndrome (VS) frequency after OHT or LVAD implantation and its relationship with 30-day mortality. Methods: A retrospective review of perioperative data, between January 2016 and December 2017, from 73 consecutive OHT and LVAD surgery adult patients at our institution was performed. VS was defined as normal cardiac output with persistent low systemic resistance requiring a norepinephrine intravenous perfusion > 0.5 µg/kg/min and the absence of sepsis or hemorrhagic shock within 48 h after surgery. Patients were all followed-up for adverse events and all-cause mortality at 30 days. Results: In our cohort of 73 patients (median age 51.7 years, 65% male patients), 25 (34%) patients developed VS. Twenty-two (30.1%) patients were on ARNI at the time of surgery, 31 (42.5%) were on other RAS blockers, 12 (16.4%) were on norepinephrine and 8 (11%) had no pre-operative drug. The pre-operative use of any vasoactive agent, was not significantly associated with VS (OR = 1.36; IC95% [0.78; 2.35]; p = 0.38). The pre-operative use of an ARNI compared to all other groups was not significantly associated with VS (OR = 2.0; IC95% [0.71; 5.62]; p = 0.19). The pre-operative use of an ARNI compared to other RAS blockers was also not significantly associated with VS (OR = 1.25; IC95% [0.37; 4.26]; p = 0.72). At 30 days, 18 (24.7%) patients had died. The pre-operative treatment with ARNI, or other RAS inhibitors was associated with a significantly lower rate of death compared to the absence of treatment (HR = 0.11; IC95% [0.02; 0.55]; p = 0.009 for ARNI and HR = 0.20; IC95% [0.06; 0.69]; p = 0.011 for other RASi). Conclusions: Preoperative use of sacubitril-valsartan was not significantly associated with development of vasoplegic syndrome in patients undergoing OHT or LVAD surgery. Furthermore, our data suggests a significant 30-day survival benefit with efficient renin-angiotensin blockade before surgery.

Hormonal Stress Response and Hemodynamic Stability in Patients Undergoing Endovascular vs. Conventional Abdominal Aortic Aneurysm Repair

Background and Aims:

To investigate the effect of two different surgical techniques with different anesthetic modes on intraoperative and postoperative hormonal stress response, hemodynamic stability, fluid loading and renal function in patients scheduled for elective infrarenal abdominal aortic aneurysm (AAA) repair.

Materials and Methods:

Forty consecutive patients scheduled for elective infrarenal AAA repair were allocated without randomizing into two groups: an endovascular (EVAR, n=20) and a conventional (CAR, n=20) aneurysm repair group according to aneurysm morphology as determined by pre-operative computed tomography and angiography. The EVAR group were operated under spinal anesthesia and the CAR group using general anesthesia with epidural blockade.

Results:

Patients undergoing CAR showed lower intraoperative mean arterial pressure and significantly higher plasma norepinephrine before aortic cross-clamping and significantly higher lactate after aortic declamping and postoperatively than patients in the EVAR group. Postoperatively, vasopressin and serum cortisol were also significantly higher in the CAR group. Fluid loading and estimated blood loss were more excessive in the CAR group.

Conclusions:

Stress response was lower and hemodynamic stability and lower body perfusion superior and renal function also better maintained in patients undergoing EVAR under spinal anesthesia as compared to those undergoing CAR using general anesthesia with epidural blockade.

Angiotensin-converting enzyme inhibition and blood pressure response during total intravenous anaesthesia for minor surgery

BACKGROUND

This study investigates whether long-term treatment with an angiotensin-converting enzyme inhibitor (ACEI) impairs the haemodynamic regulation during total intravenous anaesthesia (TIVA) for minor surgery.

METHODS

In a prospective, two-armed observational study, 36 patients undergoing TIVA for minor surgery were studied. Seventeen were taking ACEIs regularly but no other antihypertensive medication (ACEI group); 19 patients without any cardiovascular medication served as controls (non-ACEI group). Haemodynamic variables were measured every minute during induction and every 5 min during surgery. The plasma levels of renin, angiotensin II, vasopressin and catecholamines were measured before and 18 min after the induction of anaesthesia.

RESULTS

The mean arterial pressure decreased to the same extent in both the groups during the induction of TIVA. There were also no differences between the groups regarding the heart rate, systolic and diastolic arterial pressure, as well as the use of vasoconstrictors, and fluids during induction and throughout surgery. In the ACEI group, the plasma renin concentration was higher at baseline and after the induction of anaesthesia presumably due to the interruption of the negative renin-angiotensin feedback loop (P<0.05). Angiotensin II increased only in the non-ACEI group (6.2 ± 2.2 before vs. 9.6 ± 3.5 pg/ml after induction; P<0.05). In both groups, the plasma norepinephrine concentration decreased after the induction of TIVA (P<0.05). Plasma vasopressin and plasma epinephrine concentrations did not change in either group.

CONCLUSION

Long-term ACEI treatment does not further aggravate the blood pressure decrease under TIVA during minor surgery, provided the induction procedure is slow, the patient is kept well hydrated and vasoconstrictors are promptly applied.

Zur perioperativen Gabe von ACE-Hemmern

INTRODUCTION

The discussion about perioperative withdrawal or continuation of angiotensin-converting enzyme inhibitors (ACEI) remains controversial. Should it be continued to avoid peaks in blood pressure and heart rate during anesthesia? Or should it be discontinued the day before to avoid clinically relevant hypotonia? What is the greater risk? Since there are only a few studies dealing with this question, we compared the cardio-circulatory reaction during anesthesia after withdrawal and with continuation of ACEI therapy.

METHODS

A total of 100 hypertonic patients chronically treated with ACEIs were included in this prospective, randomized, double blind study. The last ACEI medication was given with the premedication in the morning (premed) or on the day before (withdrawal). Blood pressure and heart rate during induction and termination of anesthesia were compared between both groups. A threshold value for vasopressor therapy was determined to be a mean arterial pressure of 60 mmHg.

RESULTS

In the premed group Akrinor was necessary significantly more often and in higher dosages. Nevertheless, following induction the blood pressure and heart rates were significantly lower compared to the withdrawal group. The highest blood pressure and heart rate during induction and termination of anesthesia did not differ between the groups.

CONCLUSIONS

The continuation of ACEI therapy in the morning is not associated with a better control of blood pressure and heart rate but causes a more pronounced hypotension which forced a therapy more often. Patients chronically treated with ACEI should receive the ACEI the last time on the day before the operation and not with the premedication in the morning.

Effects of chronic angiotensin II receptor antagonist and angiotensin-converting enzyme inhibitor treatments on neurohormonal levels and haemodynamics during cardiopulmonary bypass

BACKGROUND

Chronic treatment with renin-angiotensin system (RAS) antagonists frequently causes deleterious hypotension during anaesthesia. We compared the effects of angiotensin II receptor antagonists (ARA) and angiotensin-converting enzyme inhibitors (ACEI) on neurohormonal levels and haemodynamics during cardiopulmonary bypass (CPB).

METHODS

Forty-four patients undergoing mitral valvular surgery who were treated with either ARA (ARA group, n=14) or ACEI (ACEI group, n=15) over 12 weeks or who were not treated with any RAS antagonist (control group, n=15) were enrolled. The plasma levels of epinephrine, norepinephrine, arginine vasopressin (AVP) and angiotensin II, and haemodynamic variables were measured before (T1) and 15 min after (T2) the start of CPB, before aortic unclamping (T3) and at skin closure (T4). Mean arterial pressure (MAP) was maintained above 60 mm Hg with phenylephrine administration during CPB.

RESULTS

The plasma epinephrine, norepinephrine, AVP and angiotensin II levels increased during CPB in all groups. Compared with the control group, the AVP level was lower at T1 in the ARA group and at T2 in the ARA and ACEI groups. The angiotensin II level was higher at T1, T2 and T3 in ARA group compared with ACEI and control groups. There were no significant differences in the epinephrine and norepinephrine levels among the three groups. The amount of administered phenylephrine during CPB was greater and MAP was lower in the ARA group compared with the ACEI and control groups.

CONCLUSIONS

Chronic ARA treatment resulted in more profound hypotension than ACEI treatment during CPB, and this may be associated with the blockade of angiotensin II receptors by ARA.

Vasopressor hormone response following mesenteric traction during major abdominal surgery

BACKGROUND

We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI2) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia.

METHODS

In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGF1 alpha (stabile metabolite of PGI2), TXB2 (stabile metabolite of thromboxane A2) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection.

RESULTS

Following MT, arterial hypotension occurred along with a substantial PGI2 release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF1 alpha (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P = 0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB2 (164 (87) vs. 58 (1) ng/L, P = 0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P = 0.001), AVP (41 +/- (18) vs. 12 (7) ng/L, P = 0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients.

CONCLUSION

Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI2 release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A2, presumably contributing to hemodynamic stability within 30 min after MT.

Hemodynamic, sympathetic and angiotensin II responses to PEEP ventilation before and during administration of isoflurane

BACKGROUND

Positive end-expiratory pressure (PEEP) ventilation and isoflurane anesthesia may opposingly affect the sympathetic nervous and renin-angiotensin systems. This study was performed to elucidate the modulatory effects of isoflurane anesthesia on the neurohumoral and cardiovascular responses to PEEP.

METHODS

Renin-angiotensin and sympathetic nervous activity were investigated in mechanically ventilated, normovolemic, chloralose anesthetized pigs before and during administration of 1.4% isoflurane. Arterial angiotensin II (AII) concentrations were measured and systemic, mesenteric, hepatic and renal spillover of norepinephrine (NE-SO) were calculated using isotope dilution. Regional hemodynamic variables were investigated in parallel.

RESULTS

PEEP10 alone moderately elevated AII levels (+12.5 +/- 4.9 pg/ml, P < 0.05) and increased systemic (+22 +/- 2.9 pmol.min.100 g-1, P < 0.05) and notably mesenteric (+32 +/- 9.6 pmol.min.100 g-1, P < 0.05) NE-SO. Blood flow decreased in all vascular beds studied. Except for in the liver, isoflurane generally reduced NE-SO compared to baseline but did not change AII concentrations. Strikingly, the sympathoexcitatory response to PEEP10 was inhibited, whereas AII increased markedly (+284 +/- 64 pg/ml, P < 0.05) during PEEP10 and isoflurane. Renal blood flow was significantly more reduced during PEEP10 and isoflurane compared to PEEP10 alone, whereas the magnitude of reductions were similar in the other vascular beds.

CONCLUSION

The data suggest that renin-angiotensin activation is important to attenuate the impact of PEEP ventilation on cardiovascular performance during administration of the sympathodepressant isoflurane. Interference with the renin-angiotensin system may cause cardiovascular decompensation in isoflurane anesthetized patients subjected to PEEP-ventilation.

Cardiovascular responses to experimental infra-renal aortic cross-clamping. Modulating effects of isoflurane, sodium nitroprusside and milrinone

BACKGROUND

Pharmacological control of blood pressure is usually indicated during aortic cross-clamping (AXC). The aim of this study was to analyze the modulation by isoflurane (ISO), sodium nitroprusside (SNP) and milrinone (MIL) of the systemic circulatory responses to a standardized infra-renal AXC.

METHODS

Chloralose-anaesthetized pigs were exposed to AXC at control (no vasoactive drugs) and during the administration of each of the drugs.

RESULTS

During control, AXC increased mean arterial pressure (MAP, 17 +/- 4%) and systemic vascular resistance (SVR, 27 +/- 7%), but induced no significant changes in cardiac output (CO), heart rate (HR), pulmonary arterial pressures, pulmonary vascular resistance or central venous pressure. Low-dose ISO (0.7%) and investigated doses of SNP and MIL did not significantly alter this response. High-dose ISO (1.4%, attenuated the AXC-induced increase in SVR, but not in MAP. All drugs decreased non-clamp MAP levels. Therefore, with low-dose ISO and with SNP or MIL, peak MAP during AXC was not significantly different from control non-clamp levels (i.e. prior to pharmacological or surgical interventions). High-dose ISO was associated with a MAP during AXC that was below control non-clamp levels.

CONCLUSIONS

The objective that during AXC MAP should not exceed control non-clamp levels was achieveable by ISO, SNP or MIL. The modulating actions of the drugs on MAP during AXC were exerted mainly through reductions in non-clamp levels. This systemic hypotension was associated with decreased CO and SVR during ISO, and with decreased SVR and increased HR during SNP and MIL. Attenuation of the AXC-induced increase in SVR was produced only by 1.4% ISO.

Angiotensin-converting enzyme inhibitors in cardiovascular anesthesia

Besides the long-term regulation of extracellular fluid volume, the RAS plays an important physiologic role in maintaining venous return and blood pressure during acute hemodynamic stresses. ACE inhibitors may therefore alter venous return and cardiac output regulation during anesthesia and surgery. This may be regarded as a drawback of ACE inhibition when other factors interfere with cardiovascular homeostasis; deleterious hemodynamic events may therefore occur when blood volume is decreased, which may be frequent during cardiovascular anesthesia and surgery. However, the alternative solution should not be to stop ACE inhibitors preoperatively. This would allow recovery of RAS control of blood pressure, but at the expense of some regional circulations. From this point of view, preliminary results from early studies during cardiovascular anesthesia and surgery showing redistribution of regional blood flow with inhibition of ACE are encouraging; whether postoperative outcome can be improved deserves further studies. At this time, the evidence is that ACE inhibition does not allow the anesthesiologist to be tolerant of hypovolemia.

Effects of halothane and isoflurane on transient renal dysfunction associated with infrarenal aortic cross-clamping

Aortic cross-clamping for reconstructive aortic surgery is associated with impairment of renal function. Halothane or isoflurane was used to assess the influence of volatile anesthesia on renal hemodynamics during aortic surgery. Nineteen patients with normal preoperative creatinine clearances who were scheduled for reconstructive aortic surgery were randomly divided into two groups: halothane group (n = 9) and isoflurane group (n = 10). Induction of anesthesia consisted of midazolam, fentanyl, and pancuronium. Anesthesia was maintained with fentanyl and halothane or isoflurane in nitrous oxide and oxygen (50/50). Systemic hemodynamics were similar in both groups throughout surgery. Before aortic cross-clamping, effective renal plasma flow (ERPF) (131I-hippuran clearance) and glomerular filtration rate (GFR) (99Tc-DTPA clearance) were significantly lower in the halothane group (118.4 +/- 25.6 and 19.7 +/- 5.2 mL/min, respectively) than in the isoflurane group (253.4 +/- 51.5 and 44.9 +/- 8.4 mL/min) (P less than 0.05 for both). During cross-clamping, the renal variables were not markedly affected in either group and remained higher in the isoflurane-anesthetized patients (232.9 +/- 47.1 and 49.5 +/- 1.2 mL/min for ERPF and GFR, respectively) than in the halothane-anesthetized patients (132.4 +/- 31.6 and 14.8 +/- 3.7 mL/min, respectively) (P less than 0.05). After aortic unclamping, ERPF increased markedly in both groups (467.8 +/- 122 and 362.5 +/- 57.7 mL/min in the halothane and isoflurane groups, respectively), as did GFR (74.8 +/- 22 and 71.8 +/- 13.1 mL/min, respectively). These results suggest that anesthesia with halothane is associated with transient renal vasoconstriction during abdominal surgery. In contrast, aortic cross-clamping during isoflurane anesthesia was not associated with renal hemodynamic impairment.

[Anesthetic consequences of hemodynamic effects of angiotensin converting enzyme inhibitors]

Angiotensin converting enzyme inhibitors (ACEI) are used increasingly to treat cardiovascular diseases, and so, therefore, the number of patients scheduled for surgery and treated preoperatively with these drugs. Haemodynamic instability has sometimes been observed during anaesthesia in these patients, leading some authors to discontinue ACEI administration before anaesthesia. However, recent physiological data concerning the renin angiotensin system (RAS) and ACEI pharmacological data may increase our understanding of the mechanisms of cardiovascular interaction between ACEI and anaesthesia. The RAS is involved in blood pressure regulation when extracellular fluid volume is decreased and in case of hypovolaemia, by inducing vasoconstriction and longterm volume regulation. Arterial vasoconstriction is the target for ACEI. However, venoconstriction may maintain venous return and cardiac output in spite of reduced blood volume. On the other hand, ACEI treatment impedes cardiac adaptation to acute changes in extracellular fluid volume. This effect may be increased by underlying pathology (especially in hypertension) as well as by anaesthesia. A combination of an increased sensitivity to acute changes in ventricular load due to treatment with ACEI and anaesthesia in hypertensive patients or in patients with cardiac failure may carry a high risk of hypotension. Specific studies on haemodynamic tolerance of anaesthesia in patients chronically treated with ACEI are required to assess the prevalence of this risk and how to manage it.