Perioperative acute hypertension-role of Clevidipine butyrate.

Arterial hypertension (AH) is one of the most common pathological conditions affecting the general population which contributes to pathogenesis of various diseases and worsens the treatment outcome (James et al., 2014). It increases the perioperative morbidity and mortality, frequently result in cancelation of surgical procedures and increases treatment-associated costs (Handler, 2006). Perioperative hypertension may occur in patients with pre-existing arterial hypertension or manifest as a de novo phenomenon (Vuylsteke et al., 2000; Varon and Marik, 2008). Induction of general anesthesia is related with significant stress and sympathetic over-activation. The systolic blood pressure (SBP) in normotensive patients may increase by up to 20–30 mm Hg, while hypertensive patients may have an exaggerated reaction—SBP in these patients may increase up to 90 mm Hg (Ahuja and Charap, 2010). On the other hand, anesthesia-induced sympathetic suppression with diminished baroreceptor reflex takes place during the maintenance phase which frequently causes sustained arterial hypotension. Postoperatively, these patients present with labile BP, frequent and rebound hypertension, and have an increased risk of postoperative complications (Goldman and Caldera, 1979; Wolfsthal, 1993). Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7 and JNC-8) classifications and guidelines are currently applicable to perioperative patients as well (James et al., 2014; Chobanian et al., 2003). According to JNC-7 guidelines for evaluation and treatment of hypertensive emergencies, an immediate intervention is required in cases of hypertensive emergencies to reduce the SBP by 10–15% (no more than 25%) within the first hour. Reduction of the absolute BP to 160/110 mmHg should be done gradually over the following 2–6 h (Aggarwal and Khan, 2006; Flanigan and Vitberg, 2006; Pollack and Varon, 2008; Varon, 2008; De Gaudio et al., 2009; Hays and Wilkerson, 2010; Kuppasani and Reddi, 2010; Smithburger et al., 2010; Polly et al., 2011). Only in patients with aortic dissection, the SBP should be reduced to less than 120 mmHg within 20 min. In hypertensive emergencies associated with ischemic stroke, BP must be decreased to less than 180/110 before thrombolytic therapy may be administered (Pollack and Varon, 2008; Varon, 2008; De Gaudio et al., 2009; Hays and Wilkerson, 2010; Polly et al., 2011). Abrupt BP reduction should be avoided as it can result in critical blood flow reduction and ischemic end organ damage (Varon, 2008; De Gaudio et al., 2009; Smithburger et al., 2010; Polly et al., 2011). Since overshooting a target BP in hypertensive patients is associated with worse outcome, many treatment protocols require invasive arterial blood pressure monitoring during anesthesia in high risk cases (Pollack and Varon, 2008; Rhoney and Peacock, 2009). Hypertensive emergencies should be treated aggressively, using quick-onset intravenous medications, whereas hypertensive urgencies do not always require such aggressive treatment. Longer acting oral medications (labetalol, clonidine, etc.) may be more appropriate in situations of hypertensive urgency. However, caution should be exercised when using antihypertensive agents in the acute setting. An overly aggressive treatment approach may lead to organ hypoperfusion (Rodriguez et al., 2010). Once the immediate threat of organ damage is diminished, BP should be gradually brought to baseline level within a period of 24–48 h (Peacock et al., 2009). Characteristics of an ideal intravenous hypertensive agent are rapid onset and offset of action, low risk of hypotension, minimal drug interaction with other medications, lack of adverse reactions, wide therapeutic window, ease of titration, preservation of renal and hepatic functions, selectivity, low cost, possibility of easy transition to oral therapy, predictable response, and lack of effects on intracranial pressure (Levy, 1999; Oparil et al., 1999). Multiple intravenous medications are currently used to control the BP in the perioperative period, and all these medications have specific advantages and limitations (Kurnutala et al., 2013). Selection of an optimal antihypertensive therapy for the perioperative period depends on the patient’s individual characteristics and locally adopted guidelines (Pollack and Varon, 2008; Belsha, 2013). Clevidipine butyrate is a Ca2+-channel antagonist that acts on the L-type Ca2+