Constrictive pericarditis is characterized by the pathologic changes of the pericardium that occur over time with chronic inflammation. Pericardial fibrosis, calcification and stiffening leave the heart unable to fully expand and fill, resulting in ventricular constriction. This fundamental pathophysiologic change in diastolic filling leads to right HF and systemic congestion (Fig. 1) [2]. Patients often present with lower extremity edema, poor exercise tolerance and hypoproteinemia. Another important pathologic change of CP is the myocardial atrophy that can occur from myocardial infiltration and fibrosis which not only impairs ventricular diastolic filling, but also affects systolic contraction and further contributes to the development of HF [9].

Fig. 1

Constrictive pericarditis pathophysiological changes

While pericardiectomy is considered the gold standard for treatment, the physiologic changes associated with CP increase the risk of surgery. Myocardial atrophy and a higher NYHA classification are independent risk factors for a poor prognosis [10]. Hypoproteinemia can affect wound healing and infection rates. Chronic liver stasis can result in hepatic dysfunction and coagulation disorders [6]. When combined with the coagulation dysfunction caused by CPB, the presence of an underlying coagulopathy can significantly increase the surgical risk [7, 8]. A recent meta-analysis with 2,114 patients showed that the operative mortality of CP was 6.9% [11]. Results from other studies also demonstrated that the mortality and morbidity associated with pericardiectomy was significantly higher than that of other cardiac surgeries [12,13,14]. Despite these statistics, all but two patients in this case series survived to discharge (96.97%) and almost all of these patients had extensive comorbidities (including congestive hepatopathy, HF, and AF) which are known to significantly increase the perioperative mortality [15, 16]. Though many factors can influence patient outcome, anesthetic perioperative management is crucial to achieving good outcomes after pericardiectomy.

Intraoperative fluid management

Patients undergoing pericardiectomy are at high risk for left HF. When the atrophied left ventricle is freed from the restraint of the scarred pericardium, it can easily be overwhelmed with the sudden increase in volume return from the dilated venous system. Additionally, acute fluid shifts can occur as the venous pressure drops and interstitial fluid is pulled back into the systemic circulation. Meticulous intraoperative fluid management is critical to the overall success of the procedure. A recent study shows that, in patients undergoing pericardiectomy, the total amount of intraoperative fluid significantly correlated with patient outcomes [18]. Minimizing intraoperative fluid infusion and using diuretics from the beginning of surgery were effective in this study. Huang and colleagues indicated that adequate preoperative preparation and a restrictive fluid strategy including the use of diuretics could prevent low CO syndrome and reduce mortality [19].

In this case series, all patients underwent strict preoperative fluid management with a weight loss of 5-10 kg. As most patients were on chronic diuretics, the urine output was meticulously followed during the case. For off-pump pericardiectomies, the target urine output during the procedure was greater than 1000mL. The systolic blood pressure was maintained greater than 90mmHg to ensure adequate renal flow. Low-dose inotropes and, if necessary, administration of vasopressors were used to achieve this goal. Close monitoring of the CVP also helped to guide management decisions. Many patients were noted to have elevated CVPs (15-20mmHg) prior to the surgery. After pericardiectomy, the CVP was kept below 8mmHg. When patients appeared to be at high risk for volume overload, they were placed in a reverse Trendelenberg position. A nitroglycerin infusion was also used to help reduce left ventricular preload if the hemodynamics allowed [17]. Intraoperative TEE monitoring of ventricles can provide a good estimate of preload and guide the fluid management.

Circulatory support

Postoperatively, it is very important for patients to maintain good myocardial contractility and a fast heart rate [19]. Inotropic agents such as epinephrine or dopamine are the drugs of choice to support cardiac function. All patients were treated with inotropes in this study. Maintaining the heart rate around 100 bpm allows the atrophic heart to recover under an affordable load. While faster heart rates are preferred, severe tachycardia should be avoided and may require treatment with amiodarone when the heart rate exceeds 120 bpm. Although β blockers or non-dihydropyridine calcium channel blockers are often the first-line rate-controlling agents, they need be used judiciously because of their strong negative inotropic effect [20, 21]. When new onset AF affects hemodynamics during pericardiectomy, timely synchronous defibrillation to restore sinus rhythm is vital to maintain circulation stability.

Perioperative bleeding

Extensive dissection during surgery, preoperative coagulation dysfunction and the use of CPB can all contribute to postoperative bleeding [22]. In our study, 85.71% of patients who required surgical re-exploration had postoperative bleeding. As many CP patients have underlying hepatic dysfunction, Vitamin K should be given prior to the surgery to increase the synthesis of coagulation factors in the liver [23]. The use of an antifibrinolytic, such as tranexamic acid, can also significantly reduce perioperative bleeding and is recommended for the duration of surgery [24,25,26]. A transfusion algorithm should be used to guide perioperative blood and blood product transfusion.

The utilization of CPB is an independent risk factor for morbidity and mortality after pericardiectomy [15, 16]. It is well known that CPB can lead to an inflammatory response, impaired coagulation function and significant organ dysfunction [27,28,29]. Although majority of our patients underwent pericardiectomy without CPB, there were still a few patients went on CPB due to combined cardiac surgical procedures instead of the severity of pericarditis. However, the patients who underwent pericardiectomy on-pump lost more blood, required more blood products and had a higher postoperative infection rate when compared to the off-pump group. To minimize the risks of CPB, it is important to complete the pericardiectomy off-pump whenever possible. When CPB is required for concomitant procedures, the pericardiectomy portion of the case should be done prior to institution of CPB.

Perioperative TEE monitoring

TEE plays an important role during pericardiectomy as it provides for real-time assessment of cardiac structure and function. Perioperative ventricular function and volume status can be assessed and used to guide inotropic support and fluid replacement. Although there may not be significant valvular pathology prior to the surgery, new onset or worsening mitral/tricuspid valve regurgitations are often observed after pericardiectomy which may be caused by increase venous return, ventricular dilation and disfunction and can adversely affect the outcomes if not treated appropriately [30, 31]. Generally, more than moderate mitral and/or tricuspid valvular regurgitations need surgical intervention. In our study, 25.76% of patients underwent valvular repair procedure due to significant worsening of valve regurgitations.