Uncontrolled systemic hypertension
It is well established that uncontrolled systemic HTN (BP 140/90 - 179/109 mmHg) is not an independent risk factor for perioperative cardiovascular complications in association with noncardiac surgical procedures.18 In association with other recognized minor predictors/markers for cardiovascular disease such as advanced age (>70 years), abnormal ECG (LV hypertrophy, left bundle branch block, ST-T abnormalities), rhythm other than sinus, and the presence of clinical risk factors such as cerebrovascular disease, diabetes mellitus and renal insufficiency, an awareness of the patient’s elevated BP should lead to a higher suspicion of coronary artery disease (CAD). These patients should be referred for routine medical evaluation and risk modification.
Severely Elevated Blood Pressure
Patients with uncontrolled systemic HTN are at increased risk for the development of severely elevated BP.20,21 Severely elevated BP is defined as SBP >180 mmHg or DBP >110 mmHg.22 The mechanisms that lead to severely elevated BP (which tends to develop gradually over days, weeks, or months) appear to be related to a failure of normal autoregulatory function and an increase in systemic vascular resistance. Moreover, concurrent endovascular injury with fibrinoid necrosis of arterioles lead to a cycle of ischemia, platelet deposition, and further failure of autoregulation as endogenous vasoactive substances are released. When patients present with severely elevated BP, clinicians should first differentiate between severe asymptomatic hypertension and hypertensive emergency (Figure 6).22
Severe asymptomatic HTN is defined as severely elevated BP without signs and symptoms of target-organ damage.12,23 It should be further classified as severe uncontrolled HTN or hypertensive urgency. Severe uncontrolled HTN is defined as the absence of risk factors for progressive target-organ damage other than HTN (e.g., unstable angina, history of congestive heart failure, or preexisting renal insufficiency).23 These patients should be referred for medical evaluation and risk modification within one to seven days of presentation.22 Hypertensive urgency is defined as the presence of risk factors for progressive target-organ damage. These patients should be referred for medical evaluation and risk modification within 24 to 48 hours of presentation.22
Hypertensive emergency is defined as severely elevated BP with signs and symptoms of target-organ damage.12,24,25 These patients require admission to an intensive care unit within one to two hours for immediate treatment and observation (Table 4). In the emergent setting (e.g., the oral healthcare setting), the BP should not be acutely lowered. Normally, tissue perfusion in the brain, heart, and kidneys is tightly regulated within a certain range of mean arterial pressure (MAP), i.e., at a constant level, despite fluctuations in systemic BP.26 Abruptly decreasing the MAP can lead to significant drop in cerebral blood flow and, thus, cerebral ischemia.22Table 4. Diagnosis and Treatment of Hypertensive Emergency in the Oral Healthcare Setting.
|Symptoms and Signs||First Response|