Right Heart Failure and Pulmonary Hypertension

In depth

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RV physiology: afterload, interdependence and perfusion

The RV free wall is 2–3 mm thick at end-diastole against 8–11 mm for the LV (Ventetuolo 2014); 5 mm or more means hypertrophy (ASE 2025). Built to move volume into a low-resistance circuit, the RV loses stroke volume sharply as mean PA pressure rises from 10 to 30 mm Hg, while LV stroke volume falls only about 10% as mean aortic pressure rises from 100 to 140 mm Hg (Ventetuolo 2014). A previously normal, thin-walled RV cannot generate a mean PA pressure above about 40 mm Hg (ESC 2019 PE), so massive PE presents as shock with only moderate PA pressures; an RV that hypertrophied over years of PAH reaches systemic pressures, then fails when a trigger adds load.

The ventricles share the septum, encircling muscle fibers and a pericardium that cannot stretch quickly. A dilating RV pushes the septum toward the LV (the D-shaped LV on echo), so the LV underfills and its stroke volume falls even with normal muscle; more fluid only widens the gap between RV and LV filling pressures (Ventetuolo 2014). LV contraction also drives part of RV systolic function through the shared septum, so LV failure weakens the RV, and an LVAD that pulls the septum left can limit RV stroke volume (ISHLT 2023).

The RV free wall is normally perfused in systole and diastole. As RV systolic pressure approaches aortic pressure, systolic right coronary flow approaches zero (Ventetuolo 2014), so hypotension starves the RV just as its demand peaks: ischemia lowers output, pressure falls further, and the spiral that vasopressors interrupt begins. A fluid bolus that dilates the RV, or a sedative or induction drug that lowers MAP, can start it.

Pulmonary hypertension: definitions, groups and home therapy

ESC/ERS 2022 defines PH as a mean PA pressure over 20 mm Hg (previously 25 or more) and pre-capillary PH as that plus a PAWP of 15 or less and a PVR over 2 WU (previously 3). Post-capillary PH has a PAWP over 15: isolated if PVR is 2 WU or less, combined if higher. The 7th World Symposium (Kovacs 2024) kept these thresholds while noting that normal PAWP tops out near 13 mm Hg. Older texts and exam items still use 25.

In group 2, PAH drugs are not recommended (ESC/ERS 2022): pulmonary vasodilation sends more flow to a left heart that cannot take it, and the INOmax label warns of pulmonary edema with LV dysfunction.

Causes in the ICU

• Acute PE: the 2026 AHA/ACC guideline sorts patients into categories A to E, with D for incipient cardiopulmonary failure (transient hypotension or normotensive shock) and E1 for recurrent or persistent hypotension, where advanced therapy (systemic lysis, catheter-based treatment, surgical embolectomy) is reasonable in selected patients; in D it may be considered. PEITHO (NEJM 2014; 1,005 normotensive patients with RV dysfunction and a positive troponin) shows the trade-off: tenecteplase cut 7-day death or decompensation from 5.6% to 2.6% but raised major extracranial bleeding (6.3% vs 1.2%) and stroke (2.4% vs 0.2%).
• ARDS: hypoxic vasoconstriction, hypercapnia, microthrombi, overdistension and high PEEP raise PVR. Acute cor pulmonale affected 22% of 752 patients on protective ventilation; pneumonia, driving pressure 18 cm H₂O or more, PaO₂/FiO₂ under 150 and PaCO₂ 48 mm Hg or more predicted it, and severe cor pulmonale carried 57% hospital mortality versus 42% (Mekontso Dessap 2016).
• LVAD: the pump hands the RV more venous return while pulling the septum away. After HeartMate II implants (Kormos 2010; 484 patients) RV failure followed 20% and 6% needed an RVAD; a CVP:PCWP ratio over 0.63, preoperative ventilation and BUN over 39 mg/dL predicted it, and 180-day survival was 71% versus 89%.
• Cardiac surgery and transplant: stunning from imperfect cardioplegia, air in the anteriorly placed right coronary, graft problems, protamine reactions and PH from long-standing mitral disease; after transplant the donor RV meets the recipient's raised PVR. Tamponade and sternal compression mimic RV failure and must be excluded (ISHLT 2023, Class I after LVAD).
• Sepsis: RV dysfunction was present in 55% of 388 septic patients with an echo, and isolated RV dysfunction predicted worse 1-year survival (HR 1.6; Vallabhajosyula 2017).
• RV infarction (inferior STEMI with ST elevation in V4R): a stunned RV facing a normal PVR is preload-dependent, so cautious fluid, AV synchrony and reperfusion help, and nitrates, diuretics and morphine harm.
• Decompensated PAH follows infection, arrhythmia, a missed or interrupted drug, pregnancy, surgery or PE; 41% of 46 PAH patients needing catecholamines died in the ICU (Sztrymf 2010).

Recognition: bedside, catheter, echo and labs

At the bedside: hypotension and tachycardia with a raised JVP and large v waves (tricuspid regurgitation), clear lungs, hepatomegaly, edema and falling urine output; a loud P₂, a parasternal heave or new flutter or AF point the same way. Congestion shows in the organs as rising creatinine, bilirubin and transaminases. BNP and troponin rise with RV strain; lactate and SvO₂ follow output.

Septal shape reads the load: an LV eccentricity index over 1 only in diastole means RV volume overload; over 1 at end-systole means pressure overload (ASE 2025). The McConnell sign (akinetic mid free wall, contracting apex) had 77% sensitivity and 94% specificity for acute PE in its derivation study (McConnell 1996), but it was as common in RV infarction (67% vs 70% in PE; Casazza 2005): it marks an acute RV insult, not PE alone.

On a PA catheter, decompensation is a high CVP with falling output and SvO₂, and a PA systolic pressure that drifts down as the RV weakens, easily misread as a response to a vasodilator. ISHLT 2023 adds a falling PA pulse pressure and a rising mean PA to MAP ratio, and warns that PAPi thresholds differ by population.

Treatment step by step

Preload. Most decompensated patients are overloaded: WSPH 2019 and 2024 put IV loop diuretics first (a continuous infusion above the home oral dose). WSPH 2024 calls renal replacement for refractory congestion controversial (high mortality, instability during dialysis): continuous hemodiafiltration only for patients without severe instability, and ECMO first in bridging candidates. As the RV shrinks, tricuspid regurgitation lessens and the septum moves back, so output often rises with fluid removal. Ventetuolo 2014 suggests RV filling pressures of about 8–12 mm Hg; fluid is for an underfilled RV only, 500 mL or less with a check of output (ESC 2019 PE).

Pressure. Norepinephrine restores the aortic-to-RV gradient and adds β₁ inotropy; WSPH 2024 names norepinephrine and vasopressin the drugs of choice and suggests a MAP of 70–75 mm Hg, without dedicated trials. Low-dose vasopressin (0.01–0.03 units/min) dilates pulmonary vessels through endothelial NO (Ventetuolo 2014) and causes fewer tachyarrhythmias (WSPH 2024). Phenylephrine raises PVR; dopamine provokes arrhythmias.

Contractility. Dobutamine starts at 2.5 mcg/kg/min and in PH should not exceed 5–7.5 (WSPH 2024), as higher doses lower SVR without raising output. Milrinone lowers PVR more but also SVR, so it usually runs with a pressor and WSPH 2024 urges caution with it in PH; it is often given without a load at 0.125–0.375 mcg/kg/min, lower in kidney failure (milrinone drip card). WSPH 2024 advises against epinephrine in decompensated PH (tachycardia, lactate), although after cardiac surgery it is a common RV inotrope (After Cardiac Surgery sheet).

Rhythm. In 231 PH patients (Tongers 2007), 84% of supraventricular tachycardia episodes caused deterioration; mortality was 6.3% when sinus rhythm was restored and 82% with persistent AF. Cardiovert early, use amiodarone or digoxin rather than β-blockers or calcium channel blockers (WSPH 2024), and pace heart block with AV synchrony.

Gas exchange. Keep SpO₂ above 90% (WSPH 2019 and 2024) or 92% (Ventetuolo 2014) and PaCO₂ and pH near normal (after LVAD, ISHLT 2023 targets PaCO₂ 35–40), and treat fever, pain, agitation and shivering.

Inhaled nitric oxide and epoprostenol

Inhaled vasodilators reach only ventilated alveoli, so they lower PVR and improve ventilation-perfusion matching without systemic hypotension. Both are off-label in adults: the INOmax label (2023) covers neonates at 20 ppm, and inhaled epoprostenol is the IV drug, nebulized.

Evidence supports physiology, not outcomes. In PAH, inhaled NO 20 ppm and epoprostenol 50 ng/kg/min lowered PVR about equally (14% vs 12%; Preston 2013). In ARDS, inhaled NO did not lower mortality (38.2% vs 37.5%) and raised renal failure (RR 1.59; Cochrane, Gebistorf 2016). After LVAD, 40 ppm did not significantly reduce RV dysfunction (9.6% vs 15.6%; Potapov 2011), and in intermediate-risk PE 50 ppm did not significantly improve an RV and troponin endpoint (iNOPE, Kline 2019). ISHLT 2023 still suggests inhaled vasodilators or milrinone for RV dysfunction after LVAD (IIa).

Both act for minutes or less, so a sudden stop can cause rebound PH with hypoxemia, hypotension, bradycardia and low output; restart at once (INOmax label). Wean in steps hours apart, keep the drug running through transport and circuit changes, and check the delivery system if circuit NO₂ reaches 3 ppm (label). A PDE5 inhibitor before the last step prevented rebound in a pediatric trial (0 of 15 vs 10 of 14; Namachivayam 2006); adult data are case reports.

Intubation and ventilation

WSPH 2019 advises avoiding intubation whenever possible in severe RV failure, and WSPH 2024 calls induction the critical phase: sedatives lower SVR and venous tone, positive pressure raises PVR and cuts venous return, and apnea brings hypoxemia and hypercapnia, so MAP falls below what the RV needs to perfuse itself. Arrest is rarely survivable: of 132 CPR attempts in PAH patients, 8 (6%) were alive at 90 days (Hoeper 2002).

1. Bridge with HFNC or NIV if possible; call the most experienced operator and the PH or ECMO team (awake VA-ECMO may come first in PH centers).
2. Arterial line; norepinephrine running to hold MAP above PA pressure (Mosier 2015); push-dose pressor drawn up.
3. Inhaled NO or epoprostenol running during preoxygenation (Mosier 2015); avoid any desaturation.
4. Etomidate or ketamine at reduced doses; avoid propofol boluses; aim for first-pass success to keep apnea short.
5. After: tidal volume about 6 mL/kg, plateau under 30 cm H₂O, PEEP used with caution (ESC 2019 PE); expect to raise the pressor.

PVR is lowest near functional residual capacity, rising with atelectasis and hypoxia at low lung volumes and with overdistension at high ones. In ARDS, RV-protective ventilation (Vieillard-Baron 2016) means a low driving pressure, limited hypercapnia, PEEP matched to recruitability and prone positioning; watch for auto-PEEP.

Mechanical support

Support should come before lactate, creatinine and bilirubin show irreversible damage; ISHLT 2023 makes early RVAD for refractory RV failure after LVAD Class I (LOE C). A failing RV facing a near-normal PVR (after LVAD, RV infarction, cardiotomy, transplant) can be bypassed with a right-sided pump; in severe pre-capillary PH, forcing flow through a high-resistance bed is suboptimal (WSPH 2024), and VA-ECMO goes around the lungs.

RECOVER RIGHT (Anderson 2015; 30 patients after LVAD, cardiotomy or MI) raised CI from 1.8 to 3.3 L/min/m² and lowered CVP from 19.2 to 12.6 mm Hg with the Impella RP, with 73.3% 30-day survival after a mean 3 days. A right-sided pump needs an LV that can take the extra return; if wedge climbs, a left-sided pump or VA-ECMO is added. In PH centers, VA-ECMO in an awake, non-intubated patient bridges to transplant or recovery, often at 2.5–3.5 L/min (WSPH 2024).

Nursing care and home prostacyclin lines

• Hemodynamics: MAP against target; CVP and PA trends read together (falling PA pressure with rising CVP is bad news); CI and SvO₂; rhythm alarms for AF.
• Volume: strict intake and output, daily weight, urine response to each diuretic dose, concentrated infusions, CRRT goals each shift.
• Respiratory: SpO₂ over 90–92%, PaCO₂ and pH, inhaled NO with methemoglobin and NO₂; no unplanned circuit breaks; in flight, raise FiO₂ or ask for a lower cabin altitude, since altitude hypoxemia raises PVR.
• Organs: creatinine, bilirubin and transaminases as congestion markers.
• Comfort: treat pain, agitation, fever and shivering; choose sedation with BP in mind.

Home IV epoprostenol or treprostinil arrives with a tunneled line, a portable pump and a dose in ng/kg/min. Epoprostenol's half-life is 6 minutes or less, it must not be mixed with other drugs, and interruption has caused rebound PH and death (Veletri label); treprostinil's terminal half-life is about 4 hours, and abrupt withdrawal still worsens PAH (Remodulin label). Keep the home pump running, or convert to a hospital pump only with the PH team, a pharmacist and a second nurse checking drug, concentration, dose and rate. Never flush, sample from or piggyback into the line, and keep a spare cassette or bag ready.

If the line or pump fails, run the same dose through a peripheral IV at once (Veletri allows temporary peripheral infusion until central access is established) and call the PH team. Treprostinil restarted within hours can resume its rate; longer gaps need re-titration (Remodulin label).

Unsettled: whether inhaled vasodilators improve outcomes in any adult group, the best MAP target, dobutamine versus milrinone versus low-dose epinephrine, the timing of RV support, and right-sided pumps versus VA-ECMO in PE and PAH.

Exam pearls

• RV failure: hypotension, high CVP, clear lungs, CVP near or above wedge, output falling as CVP rises.
• RV infarct (ST elevation in V4R): cautious fluid and AV synchrony; avoid nitrates, diuretics and morphine.
• Chronic RV failure with a high CVP: diurese or ultrafilter; a bolus lowers output.
• PH is a mean PA pressure over 20 mm Hg; pre-capillary adds PAWP 15 or less and PVR over 2 WU (ESC/ERS 2022).
• Left heart disease (group 2) is the commonest cause of PH, and PAH drugs are not used for it.
• Hypoxemia, hypercapnia and acidosis raise PVR; keep SpO₂ over 90–92% and PaCO₂ normal.
• Norepinephrine and vasopressin keep aortic pressure above PA pressure; phenylephrine raises PVR.
• Inhaled NO: 20 ppm, methemoglobin within 4–8 h, NO₂, rebound if stopped abruptly, pulmonary edema in LV failure.
• McConnell sign marks an acute RV insult (PE, but also RV infarction); a septum flattened in systole means RV pressure overload.
• Never interrupt IV epoprostenol (half-life 6 minutes or less); restart through a peripheral IV if the line fails.