2024
The casting of invasive cardiopulmonary exercise testing: towards a common goal.
Singh I, Waxman A. The casting of invasive cardiopulmonary exercise testing: towards a common goal. European Respiratory Journal 2024, 64: 2400783. PMID: 38991723, DOI: 10.1183/13993003.00783-2024.Peer-Reviewed Original ResearchStiffening of the human proximal pulmonary artery with increasing age
Manning E, Mishall P, Ramachandra A, Hassab A, Lamy J, Peters D, Murphy T, Heerdt P, Singh I, Downie S, Choudhary G, Tellides G, Humphrey J. Stiffening of the human proximal pulmonary artery with increasing age. Physiological Reports 2024, 12: e16090. PMID: 38884325, PMCID: PMC11181131, DOI: 10.14814/phy2.16090.Peer-Reviewed Original ResearchConceptsProximal pulmonary arteriesPulmonary arteryAge-related stiffeningRight ventricular ejection fractionVentricular ejection fractionMean wall thicknessEjection fractionNo significant differenceSystemic circulationLuminal caliberDiffusing capacityArterial stiffeningIncreasing ageSignificant differenceDistensionArteryWall thicknessAdverse effectsWall strainVessel diameterCyclic biaxial strainOrgan donorsAgeMicrostructural remodeling
2023
Post-Acute Sequelae of SARS-CoV-2 More Than Deconditioning
Joseph P, Singh I. Post-Acute Sequelae of SARS-CoV-2 More Than Deconditioning. CHEST Journal 2023, 164: 583-584. PMID: 37689472, DOI: 10.1016/j.chest.2023.03.014.Peer-Reviewed Original ResearchCognitive impairment in pulmonary arterial hypertension
Heller S, See C, Singh I, Fredericks C. Cognitive impairment in pulmonary arterial hypertension. Annals Of Clinical And Translational Neurology 2023, 10: 1899-1903. PMID: 37550957, PMCID: PMC10578884, DOI: 10.1002/acn3.51867.Peer-Reviewed Original ResearchConceptsPulmonary arterial hypertensionCognitive impairmentArterial hypertensionPulmonary artery pressureRight heart dysfunctionPulmonary vascular remodelingCognitive impairment syndromeVascular cognitive impairmentArtery pressureCardiopulmonary exerciseHeart dysfunctionNoninvasive markerCognitive dysfunctionVascular remodelingAdult subjectsImpairmentHypertensionUnderlying mechanismAbnormal increaseDysfunctionSyndromeCognitive evaluationSubjectsHigh-Risk Pulmonary Embolism: Management for the Intensivist
Khosla A, Zhao Y, Mojibian H, Pollak J, Singh I. High-Risk Pulmonary Embolism: Management for the Intensivist. Journal Of Intensive Care Medicine 2023, 38: 1087-1098. PMID: 37455352, DOI: 10.1177/08850666231188290.Peer-Reviewed Original ResearchConceptsHigh-risk pulmonary embolismHigh-risk PE patientsPulmonary embolismRisk stratificationPE patientsTreatment optionsRisk pulmonary embolismMassive pulmonary embolismIntensivist’s perspectiveReperfusion therapySupportive careAcute managementPatientsIntensivistsSupport optionsEmbolismHigh rateCarePhysiological consequencesOutcomesTreatmentOptionsStratificationMorbidityTherapyIntegrating Right Ventricular Pressure Waveform Analysis With Two-Point Volume Measurement for Quantification of Systolic and Diastolic Function: Experimental Validation and Clinical Application
Heerdt P, Martin-Flores M, Oakland H, Joseph P, Singh I. Integrating Right Ventricular Pressure Waveform Analysis With Two-Point Volume Measurement for Quantification of Systolic and Diastolic Function: Experimental Validation and Clinical Application. Journal Of Cardiothoracic And Vascular Anesthesia 2023, 37: 1929-1937. PMID: 37422337, PMCID: PMC10529383, DOI: 10.1053/j.jvca.2023.06.011.Peer-Reviewed Original ResearchConceptsRight heart catheterizationHeart catheterizationDiastolic functionRV volumesBeat measuresDiagnostic right heart catheterizationReference standardRight ventricular contractilityEnd-diastolic pressurePressure waveform analysisEnd-systolic elastancePotential clinical utilityClinical applicationRV volume measurementsVolume measurementsRV contractilityRV systolicVentricular contractilityRV pressureBland-Altman analysisClinical utilityAnesthetized swineNitric oxideExperimental modelContractilityExercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Postacute Sequelae of SARS-CoV-2 More in Common Than Not?
Joseph P, Singh I, Oliveira R, Capone C, Mullen M, Cook D, Stovall M, Squires J, Madsen K, Waxman A, Systrom D. Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Postacute Sequelae of SARS-CoV-2 More in Common Than Not? CHEST Journal 2023, 164: 717-726. PMID: 37054777, PMCID: PMC10088277, DOI: 10.1016/j.chest.2023.03.049.Peer-Reviewed Original ResearchConceptsMyalgic encephalomyelitis/chronic fatigue syndromeME/CFSChronic fatigue syndromeSARS-CoV-2Fatigue syndromePostacute sequelaeCardiopulmonary exercise testingSystemic blood flowExercise pathophysiologyExertional intoleranceIntractable fatigueExercise testingAcute infectionPostexertional malaiseExercise intoleranceOrthostatic intoleranceVentilatory controlLong-term consequencesBlood flowClinical overlapSuch symptomsIntoleranceSequelaeCOVID-19Syndrome
2022
Short- and long-term noninvasive cardiopulmonary exercise assessment in previously hospitalised COVID-19 patients
Singh I, Joseph P. Short- and long-term noninvasive cardiopulmonary exercise assessment in previously hospitalised COVID-19 patients. European Respiratory Journal 2022, 61: 2201739. PMID: 36137592, PMCID: PMC9515479, DOI: 10.1183/13993003.01739-2022.Peer-Reviewed Original ResearchConceptsCOVID-19 patientsAcute respiratory syndrome coronavirus 2 infectionSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectionNoninvasive cardiopulmonary exercise testingSyndrome coronavirus 2 infectionCoronavirus 2 infectionCardiopulmonary exercise testingCoronavirus disease 2019 (COVID-19) pandemicSARS-CoV-2Disease 2019 pandemicExercise testingGlobal healthcare systemsInterval improvementExercise assessmentAerobic capacityHealthcare systemPatientsHospitalisationWorld populationPopulationInfectionMonthsPressure‐based estimation of right ventricular ejection fraction
Heerdt PM, Singh I, Elassal A, Kheyfets V, Richter MJ, Tello K. Pressure‐based estimation of right ventricular ejection fraction. ESC Heart Failure 2022, 9: 1436-1443. PMID: 35150211, PMCID: PMC8934966, DOI: 10.1002/ehf2.13839.Peer-Reviewed Original ResearchConceptsRight ventricular ejection fractionCardiac magnetic resonance imagingRight heart catheterizationPulmonary arterial hypertensionMagnetic resonance imagingRV pressure waveformsVentricular ejection fractionRV responseEjection fractionMale PAH patientsCardiac MRI measurementsReceiver operator characteristic curvePressure waveformROC curve analysisClinical reference standardOperator characteristic curveSignificant reductionMeasurements of RVEFPAH patientsArterial hypertensionHeart catheterizationSecondary outcomesStudy cohortLimits of agreementBland-Altman analysis
2021
Impaired systemic oxygen extraction long after mild COVID-19: potential perioperative implications
Heerdt PM, Shelley B, Singh I. Impaired systemic oxygen extraction long after mild COVID-19: potential perioperative implications. British Journal Of Anaesthesia 2021, 128: e246-e249. PMID: 35067364, PMCID: PMC8710396, DOI: 10.1016/j.bja.2021.12.036.Peer-Reviewed Original ResearchChronic Thromboembolic Pulmonary Hypertension: the Bench
Alba GA, Atri D, Darbha S, Singh I, Tapson VF, Lewis MI, Chun HJ, Yu YR, Maron BA, Rajagopal S. Chronic Thromboembolic Pulmonary Hypertension: the Bench. Current Cardiology Reports 2021, 23: 141. PMID: 34410515, DOI: 10.1007/s11886-021-01572-6.Peer-Reviewed Original ResearchConceptsPulmonary embolismAcute pulmonary embolismThromboembolic pulmonary hypertensionPlatelet-rich thrombiPulmonary hypertensionUncommon complicationMedical therapyPulmonary vasculatureImmune cellsAnimal modelsEndothelial cellsPathobiologyPlatelet biologyThrombusHuman samplesTherapyCurrent knowledgeSummaryThe developmentCTEPHHypertensionVasculopathyCellsComplicationsEmbolismInflammationChronic Thromboembolic Pulmonary Hypertension: the Bedside
Matusov Y, Singh I, Yu YR, Chun HJ, Maron BA, Tapson VF, Lewis MI, Rajagopal S. Chronic Thromboembolic Pulmonary Hypertension: the Bedside. Current Cardiology Reports 2021, 23: 147. PMID: 34410530, PMCID: PMC8375459, DOI: 10.1007/s11886-021-01573-5.Peer-Reviewed Original ResearchConceptsPulmonary arterial hypertensionPulmonary embolismMedical therapyRight ventricular failureThromboembolic pulmonary hypertensionAcute pulmonary embolismArterial hypertensionPulmonary hypertensionVentricular failureUncommon complicationDisease mimicsPulmonary vasculatureMultimodality approachUnderlying pathologyPercutaneous interventionCurrent diagnosisCTEPHHypertensionTherapyDiagnosisTreatmentEmbolismComplicationsEmboliSurgeryPersistent Exertional Intolerance After COVID-19 Insights From Invasive Cardiopulmonary Exercise Testing
Singh I, Joseph P, Heerdt PM, Cullinan M, Lutchmansingh DD, Gulati M, Possick JD, Systrom DM, Waxman AB. Persistent Exertional Intolerance After COVID-19 Insights From Invasive Cardiopulmonary Exercise Testing. CHEST Journal 2021, 161: 54-63. PMID: 34389297, PMCID: PMC8354807, DOI: 10.1016/j.chest.2021.08.010.Peer-Reviewed Original ResearchConceptsInvasive cardiopulmonary exercise testingCardiopulmonary exercise testingCardiopulmonary diseaseExercise testingControl participantsPeak VOExertional limitationCOVID-19Greater ventilatory inefficiencyPeak cardiac indexSex-matched control participantsCohort of patientsSystemic oxygen extractionDead space ventilationOnly mild symptomsExertional intoleranceCardiac indexPulmonary hemodynamicsAcute infectionVentilatory inefficiencyExercise intolerancePathophysiologic mechanismsMild symptomsHyperventilatory responseOxygen extractionQuantification of Arterial and Venous Morphologic Markers in Pulmonary Arterial Hypertension Using CT Imaging
Rahaghi FN, Nardelli P, Harder E, Singh I, Sánchez-Ferrero GV, Ross JC, San José Estépar R, Ash SY, Hunsaker AR, Maron BA, Leopold JA, Waxman AB, San José Estépar R, Washko GR. Quantification of Arterial and Venous Morphologic Markers in Pulmonary Arterial Hypertension Using CT Imaging. CHEST Journal 2021, 160: 2220-2231. PMID: 34270966, PMCID: PMC8692106, DOI: 10.1016/j.chest.2021.06.069.Peer-Reviewed Original ResearchConceptsExercise pulmonary hypertensionPulmonary arterial hypertensionControl subjectsPulmonary hypertensionSmall vessel volumeArterial hypertensionPulmonary arteryPulmonary vasculatureVascular tortuosityVascular volumeArterial volumePrecapillary pulmonary hypertensionCohort of patientsPulmonary vascular volumeVenous manifestationsThromboembolic diseaseCT angiogramArterial tortuosityHypertensionCT scanVessel volumeHeterogeneous diseasePatientsStudy designArteryPressure-based estimation of right ventricular ejection fraction: Validation as a clinically relevant target for drug development in a rodent model of pulmonary hypertension
Elassal A, Steppan J, Charania S, Santhanam L, Singh I, Heerdt PM. Pressure-based estimation of right ventricular ejection fraction: Validation as a clinically relevant target for drug development in a rodent model of pulmonary hypertension. Journal Of Pharmacological And Toxicological Methods 2021, 112: 107102. PMID: 34245885, PMCID: PMC8616781, DOI: 10.1016/j.vascn.2021.107102.Peer-Reviewed Original ResearchConceptsRight ventricular ejection fractionPulmonary arterial hypertensionRV pressure waveformsVentricular ejection fractionEjection fractionDepressed right ventricular ejection fractionClear prognostic significanceRight ventricular pressurePressure waveformVolume measurementsPAH therapyPulmonary hypertensionArterial hypertensionPrognostic significanceBland-Altman analysisVentricular pressureRat modelRV volumesRodent modelsDrug effectsHypertensionDrug developmentBeat intervalsRatsRelevant targetsArterial load and right ventricular-vascular coupling in pulmonary hypertension
Oakland H, Joseph P, Naeije R, Elassal A, Cullinan M, Heerdt PM, Singh I. Arterial load and right ventricular-vascular coupling in pulmonary hypertension. Journal Of Applied Physiology 2021, 131: 424-433. PMID: 34043473, PMCID: PMC8325619, DOI: 10.1152/japplphysiol.00204.2021.Peer-Reviewed Original ResearchConceptsPulmonary artery hypertensionRV-PA uncouplingPulmonary vascular resistancePressure waveform analysisRight ventriclePulmonary vascular impedancePulmonary hypertensionVascular impedanceRight heart catheterization dataRight ventricular-vascular couplingRV-pulmonary arterial couplingCpc-PH groupEjection fraction patientsHeart catheterization dataRV pressure curveRV-PA couplingLeft heart diseaseVentricular-vascular couplingSex-matched controlsAfterload parametersCpc-PHIpc-PHPH-HFpEFRV afterloadArtery hypertensionMacrophage-derived PDGF-B induces muscularization in murine and human pulmonary hypertension
Ntokou A, Dave JM, Kauffman AC, Sauler M, Ryu C, Hwa J, Herzog EL, Singh I, Saltzman WM, Greif DM. Macrophage-derived PDGF-B induces muscularization in murine and human pulmonary hypertension. JCI Insight 2021, 6: e139067. PMID: 33591958, PMCID: PMC8026182, DOI: 10.1172/jci.insight.139067.Peer-Reviewed Original ResearchConceptsRight ventricle hypertrophyPulmonary hypertensionDistal muscularizationSmooth muscle cellsHypoxia-inducible factor 2APulmonary arterial hypertension patientsLysM-Cre miceArterial hypertension patientsHuman pulmonary hypertensionHypoxia-inducible factor 1aPlatelet-derived growth factorMacrophage-conditioned mediumVentricle hypertrophyHypertension patientsDistal arteriolesMacrophage accumulationFl miceCardiovascular diseaseInterventional strategiesMuscularizationHypoxia exposureExcess macrophagesSMC proliferationLethal diseaseMuscle cellsImpact of right ventricular work and pulmonary arterial compliance on peak exercise oxygen uptake in idiopathic pulmonary arterial hypertension
Messina CMS, Ferreira EVM, Singh I, Fonseca AXC, Ramos RP, Nery LE, Systrom DM, Oliveira RKF, Ota-Arakaki JS. Impact of right ventricular work and pulmonary arterial compliance on peak exercise oxygen uptake in idiopathic pulmonary arterial hypertension. International Journal Of Cardiology 2021, 331: 230-235. PMID: 33545265, DOI: 10.1016/j.ijcard.2021.01.027.Peer-Reviewed Original ResearchConceptsRV stroke work indexPulmonary arterial hypertensionRight heart catheterizationExercise right heart catheterizationIdiopathic pulmonary arterial hypertensionIdiopathic PAHCardiac outputPA complianceArterial hypertensionRight ventricularDynes/s/Mean pulmonary arterial pressurePeak exercise oxygen uptakePeak stroke volume indexPA wedge pressurePeak cardiac indexPulmonary vascular resistanceStroke volume indexStroke work indexCardiopulmonary exercise testingPulmonary arterial pressurePulmonary arterial complianceRight ventricular workAge-adjusted multivariate modelExercise oxygen uptakePulmonary Hypertension in Pregnancy
Singh I, Horn E, Haythe J. Pulmonary Hypertension in Pregnancy. Clinics In Chest Medicine 2021, 42: 91-99. PMID: 33541621, DOI: 10.1016/j.ccm.2020.10.006.Peer-Reviewed Original ResearchConceptsPulmonary hypertensionPH patientsHigh maternal morbiditySystemic hemodynamic alterationsImmediate postpartum periodPotential deleterious consequencesMaternal morbidityHemodynamic alterationsPostpartum periodPhysiologic changesPregnancyCardiopulmonary circulationHypertensionPatientsDeleterious consequencesMorbidityMortalitySex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction
Singh I, Oliveira RKF, Heerdt PM, Pari R, Systrom DM, Waxman AB. Sex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction. CHEST Journal 2021, 159: 2402-2416. PMID: 33388286, DOI: 10.1016/j.chest.2020.12.028.Peer-Reviewed Original ResearchMeSH KeywordsAgedCardiac CatheterizationEchocardiographyExercise ToleranceFemaleFollow-Up StudiesHeart FailureHeart VentriclesHumansIncidenceMalePulmonary ArteryPulmonary Wedge PressureRetrospective StudiesSex DistributionSex FactorsStroke VolumeSystoleUnited StatesVascular ResistanceVentricular Function, RightVentricular PressureConceptsRV-PA couplingRV-PA uncouplingFemale patientsMale patientsPeak VORV contractilityEjection fractionHeart failureRight ventricular-pulmonary vascular couplingRV-pulmonary arterial couplingAge-matched control subjectsInvasive pulmonary hemodynamicsMaximum incremental exercisePulmonary arterial elastanceRV pressure waveformsPeak exercise capacityRight ventricular dysfunctionSingle-beat analysisEnd-systolic elastanceSex-related differencesPA elastanceRV afterloadVentricular dysfunctionAfterload mismatchContractile impairment