**2. Definition and classifications of pulmonary hypertension**

During the 4th World Symposium on Pulmonary Hypertension held in Dana Point, California in 2008, the thresholds for the diagnosis of PH were introduced: an mPAP ≥ 25 mm Hg was designated as manifest PH, while mPAP < 21 mm Hg was defined as normal, and mPAP from 21 to 25 mmHg was categorized as borderline. Correspondingly, echocardiographic systolic tricuspid regurgitation (TR) velocity thresholds < 2.5 m/s is defined as normal, 2.5 to 2.8 m/s as borderline, and > 2.8 m/s is highly indicative for manifest PH [1], as in Table-1.


mPAP: mean pulmonary artery pressure; TR: Tricuspid regurgitation; m/s: meter/second

#### **Table 1.** Definition of pulmonary hypertension [1]

The earliest PH Classification was introduced during a meeting sponsored by World Health Organization in 1973, basically this classification separated PH into two broad categories: primary or idiopathic (no identifiable causes can be found) and secondary (cause can be identified). Then in 1983 the Evian classification was proposed based on pathophysiological mechanism, clinical presentation and therapeutic options. PH Classification underwent two major modifications in Venice, Italy in 2003: the term idiopathic pulmonary arterial hyperten‐ sion (IPAH) replaced the term primary pulmonary hypertension and, combined pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) from separate categories into a single subcategory of pulmonary arterial hypertension (PAH) [5] [6]. The latest classification (Dana Point classification) became available in 2008 during the 4th World Symposium on Pulmonary Hypertension, in which PH is categorized into five groups: Group I: Pulmonary arterial hypertension (PAH); Group II: PH owing to left heart diseases; Group III: PH owing to lung diseases and/or hypoxeia; Group IV: Chronic thromboembolic pulmonary hypertension; Group V: Others (Tumor obstruction, fibrosing mediastinitis, chronic renal failure on dialysis). [5] [6], and is presented in Table-2.

clinical anesthesia standpoint, although mild or transient PH won't considerably complicate anesthetic management, moderate or severe PH surely can dramatically deteriorate intrao‐ peratively or postoperatively and potentially lead to acute right heart failure (RHF), cardio‐ genic shock and even death. The perioperative management of patients with PH varies depending upon the pathological features present, functional clinical classification, hemody‐ namic status, and success of current medical therapy. This chapter will review the epidemi‐ ology, etiologies, the mechanisms, especially cellular growth-related remodeling mechanisms, preoperative evaluation, intraoperative considerations and anesthetic management strategies,

During the 4th World Symposium on Pulmonary Hypertension held in Dana Point, California in 2008, the thresholds for the diagnosis of PH were introduced: an mPAP ≥ 25 mm Hg was designated as manifest PH, while mPAP < 21 mm Hg was defined as normal, and mPAP from 21 to 25 mmHg was categorized as borderline. Correspondingly, echocardiographic systolic tricuspid regurgitation (TR) velocity thresholds < 2.5 m/s is defined as normal, 2.5 to 2.8 m/s

**Invasive (mPAP) Non-invasive (systolic TR velocity)**

The earliest PH Classification was introduced during a meeting sponsored by World Health Organization in 1973, basically this classification separated PH into two broad categories: primary or idiopathic (no identifiable causes can be found) and secondary (cause can be identified). Then in 1983 the Evian classification was proposed based on pathophysiological mechanism, clinical presentation and therapeutic options. PH Classification underwent two major modifications in Venice, Italy in 2003: the term idiopathic pulmonary arterial hyperten‐ sion (IPAH) replaced the term primary pulmonary hypertension and, combined pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) from separate categories into a single subcategory of pulmonary arterial hypertension (PAH) [5] [6]. The latest classification (Dana Point classification) became available in 2008 during the 4th World Symposium on Pulmonary Hypertension, in which PH is categorized into five groups: Group I: Pulmonary arterial hypertension (PAH); Group II: PH owing to left heart diseases; Group III: PH owing to lung diseases and/or hypoxeia; Group IV: Chronic thromboembolic

and postoperative management of patients with PH.

196 Pulmonary Hypertension

Normal <21 mmHg <2.5 m/s Borderline 21-25 mmHg 2.5-2.8 m/s Manifest PH "/>25 mmHg "/>2.8 m/s

**Table 1.** Definition of pulmonary hypertension [1]

mPAP: mean pulmonary artery pressure; TR: Tricuspid regurgitation; m/s: meter/second

**2. Definition and classifications of pulmonary hypertension**

as borderline, and > 2.8 m/s is highly indicative for manifest PH [1], as in Table-1.


PAH: Pulmonary arterial hypertension; PH: Pulmonary hypertension; mPAP: mean pulmonary artery pressure; PCWP: pulmonary artery wedge pressure; TPG: transpulmonary pressure gradient (P¯pa - P¯pcw). #: all values measured at rest; +: high CO can be present in cases of hyperkinetic conditions such as systemic-to-pulmonary shunts (only in the pulmonary circulation), anemia, hyperthyroidism, etc.

**Table 2.** DANA POINT Classification of Pulmonary Hypertension [5] [6]
